I agree. My calc I professor would just silently scribble equations on the board, then turn around, gesture wildly, and shout "You see".

I remember right before the drop date, I had a 34 in the class, and he took time out of class to beg us to study because if too many people failed, he might have consequences.

The only grade left was the final. I did much worse on it than the rest of the course, but my course grade shot up to the low 70s. Sure enough, I had the like 4th highest grade in the class.