Lecture-Chalk movie

Tonight in lecture we watched a pretty entertaining movie. It was about teachers in a school and it showed how they acted to their students. Their sarcasm was hilarious. However, I think it's important to remember that sarcasm isn't always appropriate. Teachers need to know when to use it and when not to.
Only thing I didn't like about the movie was the statistic that 50% of teachers quite within the first 3 years. That's not very reassuring...