6. Dolores " Toad" Umbridge
She's a terrible teacher and a person in general, like that detention part. She also used the cruciatus curse on a student!
5. Quirrell
We don't get much screen time with him as a teacher, and he kinda got possessed, but he's still in the number 5 spot.
4. Mad Eye Moody ( Barty Crouch JR)
He helped Harry out of a lot of trouble, but he's in the 4 spot since he's how Cedric died and how Voldemort came back to life, and Barty's even freaky in the pensieve memory.
3. Gildeory Lockhart
He's bad, he faked his books and stuff like that, but I put him in number 3 anyways, cause the other 3 are worse than him.
2. Snape
He's a horrible teacher to Harry and the Griffyndors, but still, he did that cause of his childhood, and in the 7th book the truth is revealed ( no spoilers if you havent read it yet)
Lupin
RIP
Lupin is the best teacher and a good person in general, helped Harry with a lot of things and the first time I watched the Prisoner of Azkaban ( I hadn't read the book) I seriously thought he was a bad guy, but thanks for the relief Lupin. He also fought a lot to make sure Harry stayed alive, so that's another reason why's he's number 1.