As a teacher you are more or less obliged to pay the same amount of attention to everything. That can wear you down.
“Oh, you hate your job? Why didn't you say so? There's a support group for that. It's called everybody, and they meet at the bar.”
“Don't be dismayed by good-byes. A farewell is necessary before you can meet again. And meeting again, after moments or lifetimes, is certain for those who are friends.”