My Psychology teacher's like that. She kept telling us how she was glad we were going to be last batch of students she would have to teach, and made it seem like we were the worst.
She'd also constantly undergrade us. Nobody ever got above a C.
But then, her class always gets all A's in the A Levels, so no one really minds. Because we're used to getting such little marks, we;re always pushing to get higher ones, so it's really good motivation, in a way.
We have the answer...