today, i am angry with many students for many different reasons

why do teachers pour our heart and soul for our efforts to be unreciprocrated?

很累。真得很累。
虽然我不是最好的老师，不过我自认尽责。我每天全力以赴，希望能把所知道的东西好好的教给下一代。
智慧有限， 也就算了。我无法忍受的是孩子们的不争气。

you can't always depend on others to bail you out.

why must I always be the lifesaver here?

很累。真得很累。