As you know, 20% of people do 80% of the work. It's no different in our profession. In the high-functioning world of eduction, years of "heavy lifting" by a teacher can inevitably lead to burnout, health repercussions, time management issues, and yes, resentment and hostility. Get better at margin and setting personal and professional goals for your hard work. Remind yourself that you don't win awards for locking the doors each night. Stop making excuses for others, and don't listen to others who tell you to "learn to say 'no.'" You will be a much better educator in the long run and for the long-term.