The Human Diagnostic
Looking for honest stories about people, not product reviews? You're in the right place.
The Human Diagnostic isn't a how-to HVAC podcast. It's what a 45-year Master Technician notices about people after 90,000 service calls across gas plants, oil rigs, hospital preservation systems, high-rises, feedlots, walk-in freezers, and residential homes all over Central Oklahoma.
Hosted by Dave Hartzell, each episode tells a real story from a real service call. Sometimes he's driving to the job and predicting what he's about to walk into. Sometimes he just left and he's still working through what he saw. Either way, the story turns out to be about more than HVAC.
Topics you'll hear across the season:
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The customer nobody wanted to take, and what changed when someone finally did
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Why the person researching their broken AC at midnight isn't being difficult, they're scared
β
What 45 years of walk-ins, weddings, funerals, and broken water heaters teaches you about anxiety
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The tech who can fix anything but can't explain it, and why the customer doesn't trust him
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The review you can't place, the moment you never forget, the call that changed how you work
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What gets lost when we treat people like tickets, and what gets found when we don't
Whether you fix things for a living, manage people who do, or just like good stories from someone who has been everywhere and met everybody, The Human Diagnostic gives you the part of the job that never shows up in an invoice.
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The Human Diagnostic
How Fear of the Bill Wrecks a Simple AC Repair
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I had a customer about two years ago who could not let me find anything wrong with his house.
Not because the house was perfect. The house was middle-aged, normal, had its share of issues. He had called me out for what he thought was a refrigerant leak. I checked the system, found a small leak in the line set where it had been hit by a weed trimmer some years earlier, and started telling him what the repair would involve.
Before I could finish, he started explaining why it could not be a leak from the line set. He said the line set was protected. He said the weed trimmer guy had been told to stay away from it. He said it must be the indoor coil.
I said, sir, with respect, I have it on the leak detector right now. The reading is at the line set.
He said, then your detector is wrong.
This is a different episode from the customer in ep69 who could not commit to a decision because he was afraid the decision might be wrong. That customer was paralyzed by anticipated regret. The customer I am describing today is something different. He had no trouble making decisions. What he could not do was let anything in his life be a problem he had not anticipated.
I want to talk about this today because the difference between these two patterns matters, and I have been thinking about it since.
The relevant research here is Carol Dweck's work, summarized in her 2006 book Mindset. Dweck spent decades studying how people respond to evidence of their own failure or limitation. She identified two broad orientations. A growth mindset, in which the person treats failure as information about a process that can be revised. And a fixed mindset, in which the person treats failure as evidence about who they are at a permanent level.
Core line: "There are situations where the truth has to be stated and accepted, where people have to take responsibility, where saving face would be a moral evasion."
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Have you ever found yourself in an argument where you have like ironclad, undeniable proof of a fact, but the other person just doubles down on being wrong?
SPEAKER_01Oh, absolutely. It's the worst.
SPEAKER_00Right. Picture this. You're standing there, physically holding the receipts. Uh, you're reading the text message out loud, pointing at the literal evidence right in front of their face, and they look you dead in the eye and say, Nope, that's not what happened.
SPEAKER_02Aaron Powell Yeah, it creates this bizarre kind of cognitive dissonance.
SPEAKER_00Trevor Burrus, Jr.: It really does. It is a uniquely infuriating experience. You start to feel like you're losing your grip on reality, honestly. The instinct is to just, you know, shake them or tap the glass of your phone screen and yell, look at the proof.
SPEAKER_02Which I mean, we assume that presenting factual evidence will instantly update someone's understanding of this situation. And when it doesn't, your own brain really struggles to compute the error.
SPEAKER_00Exactly.
SPEAKER_02We all encounter this phenomenon. And uh if we're being completely honest, we all probably exhibit this behavior ourselves under the right or wrong circumstances.
SPEAKER_00Aaron Powell Oh, for sure. Which is why we are digging into an absolutely fascinating case study today that explores that exact psychological reflex. Our mission for this deep dive is to uncover the deep roots of why people refuse to admit they're wrong, even when they are totally cornered by reality.
SPEAKER_02It's such a common problem, but the why is super interesting.
SPEAKER_00And more importantly, we're going to extract a surprisingly practical, stress-free strategy from a really unlikely source to help you resolve these deadlocks in your own life. We have a ton of ground to cover, starting with a stack of notes from an Oklahoma-based master HVAC technician named Dave Hartzel.
SPEAKER_02Dave brings such a compelling perspective to this. I mean, he's been in the HVAC trade for 45 years.
SPEAKER_00That is a long time to be dealing with broken air conditioners.
SPEAKER_02It is.
SPEAKER_00So Dave gets called out to a standard middle-aged house. The homeowner suspects there's a refrigerant leak in his air conditioning system. Dave goes through his normal professional protocol, he pulls out his diagnostic equipment, specifically an electronic leak detector, and begins testing the system.
SPEAKER_02Just standard procedure.
SPEAKER_00Exactly. And sure enough, he finds a small leak on the line set, which is that bundle of copper pipes running outside the house to the compressor. And the cause of the leak is painfully obvious.
SPEAKER_01Super obvious.
SPEAKER_00The copper line bears the distinct, repeated scarring of being hit by a weed trimmer over the course of several summers.
SPEAKER_02Which, by the way, is a classic everyday landscaping accident. It happens to thousands of houses every single year.
SPEAKER_00Really? Just from a weed eater.
SPEAKER_02Oh, yeah. The protective casing gets worn away, the spinning plastic line slowly eats into the sauce copper, and eventually the pressurized refrigerant just escapes.
SPEAKER_00Wow. Okay. So Dave assesses the situation, walks over to the customer, explains that he located the leak, and begins detailing the repair process for that outside line. But before Dave can even finish his sentence, the homeowner shuts him down.
SPEAKER_02Just completely cuts him off.
SPEAKER_00Yes. He cuts Dave off and starts aggressively explaining to this 45-year professional why it absolutely could not be a leak from the outside line set.
SPEAKER_02And his rationale is entirely built on his own previous instructions.
SPEAKER_00Right.
SPEAKER_02He insists that he explicitly told his lawn care guy to stay far away from that specific piece of equipment. Because he gave those instructions, he deduces that the line set is safe, and therefore the leak must be located deep inside the house in the indoor coil.
SPEAKER_00Okay, let's unpack this for a second because the physical comedy of the standoff is amazing to visualize.
SPEAKER_02It really is.
SPEAKER_00Dave is literally holding a piece of specialized diagnostic equipment. The leak detector is actively beeping. It is registering the chemical presence of the refrigerant at the line set, right in front of both of them. It's right there. Dave even tries the polite deferential approach. He says, Uh, sir, with respect, I have it on the leak detector right now. The reading is right here at the line set.
SPEAKER_02And the customer's response is just wild.
SPEAKER_00He looks at the beeping machine, looks at Dave, and says, Then your detector is wrong.
SPEAKER_02He essentially rejects objective reality rather than update his internal narrative.
SPEAKER_00I mean, in that moment, the temptation to lose your professional composure is immense. I think most people would point at the beeping wand and say, Look at the machine. It is designed to do one single thing and it is doing it right now.
SPEAKER_02Right. Because the logic is undeniable.
SPEAKER_00But Dave holds back.
SPEAKER_02Yeah. Dave recognizes a crucial dynamic shifting in the conversation. He notices that the harder he leans on the physical evidence, the more he mentions the beeping detector, the more rigidly the customer clings to his completely unverified alternative theory about the indoor coil.
SPEAKER_00It just makes him more stubborn.
SPEAKER_02Exactly. Drawing on decades of de-escalation experience, Dave realizes this customer isn't actually arguing about the air conditioner anymore.
SPEAKER_00Which seems entirely counterintuitive. They are standing next to an air conditioner, discussing refrigerant, holding HVAC tools.
SPEAKER_02I know, it looks like an argument about machinery.
SPEAKER_00But underneath the surface, something else is driving the conflict. To understand why a grown man would straight up ignore a scientific instrument, we really have to look at what's happening in his brain.
SPEAKER_02Specifically, a psychological reflex called the identity defense.
SPEAKER_00Right. So where does this come from?
SPEAKER_02Well, a great framework for this comes from the groundbreaking work of psychologist Carol Dweck, which she detailed in her 2006 book, Mindset. Dweck spent decades studying how human beings respond to evidence of their own failure or limitations.
SPEAKER_00Okay, the whole mindset thing.
SPEAKER_02Yes. She identified two broad psychological orientations: the growth mindset and the fixed mindset. In a growth mindset, a person processes failure as just, you know, neutral data.
SPEAKER_00Like it doesn't mean anything about them personally.
SPEAKER_02Exactly. It's simply information about a process that needs to be revised. If you fail a math test, the data suggests you just need to adopt a different study strategy.
SPEAKER_00Okay, I'm a bit stuck here though on how this maps to our scenario. When I read Dweck's research, it usually focuses on like school children, academics, or athletes. It's about innate intelligence versus effort.
SPEAKER_02Right, that's the usual context.
SPEAKER_00So how does failing a math test connect to a middle-aged guy arguing about a weed trimmer?
SPEAKER_02The connection lies in how we attach our core identity to our domains of competence. In a fixed mindset, failure is not treated as data about a process, it is treated as permanent, devastating evidence about the person's underlying identity.
SPEAKER_00Oh wow. So it's a direct attack on who they are.
SPEAKER_02Yes. If you fail the math test in a fixed mindset, it doesn't mean your study habits are bad. It means you are fundamentally unintelligent.
SPEAKER_00Ouch. Okay, I see.
SPEAKER_02Now, if we apply that to our homeowner, he has tied his identity to being a highly competent property manager. His internal logic is operating like a strict mathematical formula.
SPEAKER_00Because he told the guy what to do.
SPEAKER_02Right. He gave explicit instructions to the lawn guy. If the lawn guy hit the pipe, his instructions failed. And if his instructions failed, he failed.
SPEAKER_00So his psychological immune system recognizes this beeping leak detector not as diagnostic data, but as a direct existential threat to his ego.
SPEAKER_01Exactly.
SPEAKER_00The machine is essentially beeping out the message, you are a bad manager.
SPEAKER_02That is a perfect way to visualize it. When the ego is threatened in a fixed mindset, the brain's amygdala often hijacks the prefrontal cortex. It triggers a literal fight or flight response.
SPEAKER_00So he's fighting the machine.
SPEAKER_02He is attacking the evidence to keep his identity safe. Accepting that there is a broken AC line outside isn't just about paying for a repair invoice. The psychological cost of dismantling his carefully constructed self-image is simply too high.
SPEAKER_00He just can't afford to be wrong.
SPEAKER_02To protect his identity, the physical laws of chemistry and a beeping detector simply have to be wrong instead.
SPEAKER_00You know, this reminds me of a behavioral pattern we explored in a previous deep dive. Uh, the file we looked at regarding the psychology of purchasing decisions in episode 69.
SPEAKER_02Oh, right. The anticipated regret concept?
SPEAKER_00Yeah. We discussed a type of customer who was completely paralyzed by anticipated regret. They were absolutely terrified to make any decision just in case it turned out to be the wrong one, because being wrong would crush their self-esteem. I remember that. But there is a disconnect for me here. This weed trimmer guy doesn't seem paralyzed at all. He seems perfectly comfortable planting his flag and making a very firm, albeit totally irrational, decision.
SPEAKER_02Well, that distinction actually highlights two different manifestations of the same underlying fear. The customer from our previous deep dive was trapped in a pre-decision pattern.
SPEAKER_00Oh, okay. So before they even do anything.
SPEAKER_02Exactly. Their fear of failure prevented them from taking any action at all. They couldn't even leave the starting line. But the fixed mindset homeowner today suffers from a post-decision pattern.
SPEAKER_00Because he already committed to the narrative.
SPEAKER_02Precisely. He made the decision to manage the lawn guy. He committed his ego to the belief that he had handled the situation flawlessly. What he cannot tolerate is unanticipated information after the fact that contradicts the conclusion he's already finalized.
SPEAKER_00The ink is already dry in his mind.
SPEAKER_02Right. The psychological hit of revising his self-image after he has publicly declared his competence, that is the trigger.
SPEAKER_00Okay, so we know why the customer is trapped in this intense identity defense. His brain is basically treating the leak detector like a physical attack. But Dave still has a job to do. He still has to fix the air conditioners so this guy's house can cool down. How do you actually bypass someone's amygdala when logic and physical evidence are completely useless?
SPEAKER_02This is where Dave executes an absolute masterclass in de-escalation, utilizing a technique we can call calibrated communication.
SPEAKER_00Calibrated communication? I like that.
SPEAKER_02Dave realizes that engaging the defense mechanism only strengthens it. So he stops arguing the evidence. He doesn't raise his voice, he doesn't point at the leak detector again, and he certainly doesn't demand the customer acknowledge reality.
SPEAKER_00He just completely changes the entire architecture of the conversation.
SPEAKER_02He really does.
SPEAKER_00Dave calmly looks at the homeowner and says, Sir, I'm gonna leave the diagnosis aside for a minute. Whatever caused it, the leak is real, the system is low on charge, and we need to fix it.
SPEAKER_02Which is undeniable.
SPEAKER_00Right. And then he asks, Would you like me to repair the lines set as the most likely candidate, or would you prefer I dig into the indoor coil first?
SPEAKER_02The phrasing there is incredibly precise.
SPEAKER_00It's so smart.
SPEAKER_02Notice the specific words he uses. The most likely candidate.
SPEAKER_00And neurologically, it works like a charm.
SPEAKER_01It diffuses the whole situation.
SPEAKER_00The customer pauses, thinks about it, and agrees to let Dave fix the line set first as a sort of diagnostic test.
SPEAKER_01Which is all Dave needed.
SPEAKER_00Right. Dave repairs the outside line, he recharges the system, the repair holds perfectly, cold air starts blowing inside the house, and the indoor coil, the homeowner's grand unshakable theory, is simply never mentioned again.
SPEAKER_02Dave successfully neutralized the threat. He provided a pathway to resolve the mechanical issue without forcing the homeowner to experience the psychological pain of being proven wrong.
SPEAKER_00Now, I do want to push back on this strategy for a moment because the source notes include a reaction from a younger technician who heard Dave tell this story, and I deeply empathize with his initial frustration.
SPEAKER_02Oh, sure, it can feel like a cop-out.
SPEAKER_00The young tech essentially asks, isn't this just lying? Dave knows for a fact the customer is wrong. He knows exactly where the leak is and how it happened. By presenting the repair as a mere hypothesis, a likely candidate, isn't Dave just letting the guy live in a delusion?
SPEAKER_02That reaction is completely understandable, but it really misinterprets the goal of the interaction. Dave's approach isn't dishonest. He didn't fabricate anything.
SPEAKER_00He didn't say, Yeah, a ghost hit the pipe.
SPEAKER_02Exactly. He never looked at the customer and said, you know what, you're right, the lawn guy definitely didn't do it. Instead, Dave stated the undeniable shared reality. The system's low on charge and needs to be fixed.
SPEAKER_00So he just shifts the focus.
SPEAKER_02What Dave provided is known in negotiation and conflict resolution as a face-saving frame.
SPEAKER_00By using the word hypothesis, he separates the physical repair of the copper pipe from the emotional blame of the property management.
SPEAKER_02Precisely. A face saving frame lowers the cortisol in the room. The core insight Dave had was recognizing his actual objective.
SPEAKER_00Which was getting the AC running.
SPEAKER_02Right. His objective was not to win a high school debate about lawn care management. By framing the repair as testing a hypothesis, he allowed the customer to adjust his behavior, authorizing the repair work, without having to officially revise his identity or admit his instructions had failed. It's a win-win.
SPEAKER_00There's a quote from Dave in his notes that I think operates as the thesis statement for this entire deep dive. He writes, The truth I delivered was the truth that mattered. The truth I withheld was the truth he had already decided not to receive.
SPEAKER_02That is a profound articulation of relational intelligence.
SPEAKER_00Right. The truth he had already decided not to receive.
SPEAKER_02Dave recognized that forcing the customer into a corner, making him verbalize that the lawn guy hit the pipe, wouldn't make the AC blow any colder. It would only cause the customer to dig his heels in deeper, potentially leading to Dave being fired off the job.
SPEAKER_00And then nobody gets cold there.
SPEAKER_02Exactly. Withholding that specific, ego-damaging slice of reality cost Dave absolutely nothing, but it gained him everything he needed to complete the task.
SPEAKER_00So what does this all mean for the rest of us? I mean, most of us are not HVAC technicians diagnosing copper pipes, but I guarantee every single person listening deals with this exact psychological pattern in their daily life. Oh, constantly. Think about a stubbornly rigid spouse, a difficult parent, or a coworker who consistently misses deadlines but just refuses to accept accountability.
SPEAKER_02The fixed mindset defense mechanism is universal. We see it in boardroom disputes over failed marketing campaigns, just as often as we see it in kitchens over how to properly load a dishwasher.
SPEAKER_00Oh, the dishwasher argument, a classic. But our absolute default setting in those moments, especially when we know we have the proof, is to rub their nose in it.
SPEAKER_02We want that vindication.
SPEAKER_00Yes. We pull up the email thread from three weeks ago, we find the old text message, and we dramatically present it like a lawyer in a courtroom movie, expecting them to finally break down and say, Wow, you are so right, I was completely wrong.
SPEAKER_02But as Dweck's research on the amygdala hijack shows us, and as Day's experience confirms, the courtroom approach almost never yields the desired result.
SPEAKER_00It just makes things worse.
SPEAKER_02The proof doesn't act as a clarifying agent, it acts as an accelerant. It triggers their identity defense.
SPEAKER_00So if they just fight back harder.
SPEAKER_02They immediately start attacking the source of the proof, questioning your memory, changing the subject, or simply getting angry to deflect from the ego threat.
SPEAKER_00So the strategy you need to adopt isn't about trying to convert the mindset of the stubborn people in your life. You are not going to fundamentally rewire your coworkers' childhood psychology during a tense Thursday afternoon meeting about a missed deadline.
SPEAKER_02Definitely not.
SPEAKER_00The trick is finding a graceful exit for their ego.
SPEAKER_02You construct a face-saving frame, you find a way to let them be right in a very narrow, superficial sense, or at least avoid explicitly forcing them to wear the label of wrong.
SPEAKER_00Just to get things moving again.
SPEAKER_02You offer a hypothetical structure so that the underlying practical issue, getting the project done or getting the dishwasher run, can actually be resolved.
SPEAKER_00I do want to insert a really important caveat here, pulling from a crucial distinction in the source material. By discussing face-saving frames, we are absolutely not advocating for letting people off the hook for serious moral wrongs or malicious behavior.
SPEAKER_02Oh no, that is a vital boundary to establish. There is a massive operational difference between navigating a fragile ego over a minor household issue and actively enabling a toxic situation.
SPEAKER_00Right. If someone is being emotionally abusive, committing fraud at work, or doing something that actively harms others, you do not offer them a face-saving frame.
SPEAKER_02Absolutely not.
SPEAKER_00You don't look at missing company funds and say, well, let's just treat this embezzlement as a likely candidate for our budget shortfall.
SPEAKER_02Yeah, that would be terrible advice. In those situations, the truth has to be stated clearly, boundaries must be enforced, and people have to be held fully accountable.
SPEAKER_00Because at that point, it's not about fixing an AC unit.
SPEAKER_02In situations involving actual harm or severe ethical breaches, allowing someone to save face is no longer calibrated communication. It becomes moral evasion.
SPEAKER_00Moral evasion. That's a great way to put it.
SPEAKER_02The ethical application is clear. You utilize face-saving frames to lubricate the minor frictions of daily life, not to obscure cruelty or deception.
SPEAKER_00But for the vast majority of our daily conflicts, the petty disputes over who left the garage door open, the broken air conditioners, the minor office miscommunications, fighting over whose fault it is usually fails to achieve the actual objective.
SPEAKER_02And it significantly damages the relationship along the way.
SPEAKER_00The overarching goal is to get the garage door closed, not to win a trial.
SPEAKER_02Implementing this requires a significant amount of self-regulation, though. You have to be willing to check your own ego.
SPEAKER_00Which is hard.
SPEAKER_02It is. You have to intentionally forfeit the dopamine hit of saying, I told you so, in order to efficiently solve the problem at hand.
SPEAKER_00Giving up that vindication is incredibly hard to do. It goes against all our instincts. But the next time you find yourself hitting that brick wall of denial, the next time you are holding the undeniable proof and the other person simply refuses to see it, I want you to remember Dave Hartzel.
SPEAKER_02Stop pointing at the machine.
SPEAKER_00Stop pushing the wall. Stop tapping the glass on your beeping leak detector. Take a breath, manage your own frustration, and figure out how to offer a face saving frame. Give them a way to fix the line set first, keeping their pride intact while you get the job done.
SPEAKER_02It is a remarkable, deeply empathetic tool for navigating the complexities of human relationships.
SPEAKER_00It really shifts how you view conflict. And it leaves us with one final, incredibly provocative thought from Dweck's research to mull over.
SPEAKER_02Oh, this is the really challenging part.
SPEAKER_00It is. These fixed protective patterns don't just spontaneously appear in adulthood. They often take root very early in childhood. Specifically, Dweck found that these fixed mindsets tend to develop if we are consistently praised for being smart or having natural talent rather than being praised for our effort, our resilience, or for trying a new process.
SPEAKER_02Because if your foundational identity is built entirely on the premise that you are naturally flawless and effortlessly intelligent, then any mistake, no matter how small, feels like a catastrophic threat to your very existence.
SPEAKER_00So let's turn the mirror around for a second. We spent this entire time analyzing other people, the stubborn customer, the difficult coworker, the defensive spouse. But look at your own life.
SPEAKER_02What's your blind spot?
SPEAKER_00What is the indoor coil in your own world right now? Where are you secretly rejecting undeniable evidence, doubling down on a bizarre alternative explanation simply because admitting you need to revise your approach feels like a devastating attack on who you are?
SPEAKER_02It's a tough question to answer, honestly.
SPEAKER_00It really is. Keep an eye out for those beeping leak detectors in your own mind. They might just be trying to tell you something important.