Oh man. In undergrad I had a Thermodynamics professor who used the DRAFT VERSION of his textbook to teach with. It was completely unedited and he expected us to catch any errors. He was also like 80 years old, doddering, hard of hearing, forgetful, didn't give us a syllabus until halfway through the semester.... It's the only class in undergrad that I got less than a B in. Years later I still resent him lol