Bad Teacher is not a top movie, even with the two big stars it has (Cameron Diaz & Justin Timberlake), but it's very entertaining if you take it with the grain of salt it requires. The gym teacher's humor is pretty solid, and you should watch the rest of flick with he same kind of eye to appreciate it. The ending is too easy, if funny, I'll grant that, however, it's tolerable.
Watch it on a rainy day, it'll make you smile.
6*/10