In middle school, my math teacher gave another student a detention for not doing an extra credit assignment. Kid then decided that he and the teacher were mortal enemies or something. For the next month or so, every class they would get into an argument for a few minutes or so.
I had a teacher like this too, fuck that cunt. Bitch decided she hated me like first day of class. And I just decided I hated her, too, and would do anything to get revenge. She would sometimes just throw me out of class the moment she came in, and I would yell "I didn't even do anything yet!" Even though I did have something planned.