Often you get students who just think that they can buy passing the next test. It's pretty much impossible to make them improve.
By the way, I hated chemistry at school, because the teaching was invariably so poor . Exactly what you say: dump tons of facts on people's heads and then demand them in the tests. Lately I was thinking that since I now have quite some knowledge of quantum mechanics and thermodynamics, it would be a good time to finally get into the high school chemistry . Sadly I have no time for anything like that.