Like one guy I didn't learn a thing from, because he constantly mumbled and wrote in really tiny print on the whiteboard... yet the class before each test, he'd discuss every single test question in detail and tell us the answers.
A friend of mine had him for something else, and at one point after delivering a graded test, he said "if you didn't like your grade, give your test back to me and I'll give you more points". My friend, who got a 95, decided to give it back out of sheer curiosity and got back a 98.
Edit: Hey, I have another story about this dude: another friend of mine had him for a class. This friend is legally blind, so he once asked for more time to take the test since it takes him longer to read everything. A perfectly reasonable request: it's even listed on the form of accomodations offered by the university's Disability Services. Well, when the professor filled out the form, he granted my friend literally every single disability accomodation the university offered. He ended up with dozens of accomodations he didn't even ask for