I never had any problems with substitude teachrs in highschool (because apparently its more likely that we wont even have a lesson at all, if the teacher is absent), but back in elementary, our substitude teachers could get reaaallly stupid at times.
One time I disagreed with the teacher about something she said that wasnt related to the class. Gave me detention because I "was disturbing the teaching"... I only said once that I disagreed with her. Can't remember what it was though.
Another substitude dropped our class's cd player on the floor and immidiately started yelling at someone else for something they never did...