I'm not sure if it's the worst, but it was one of the most upsetting. Back in Grade 4, I think, my French class was in the library getting books, and working on an assignment. After 25 kids had rummaged over the French section in the library, it obviously looked trashed and pillaged. Well, I was practically the last one there, which left me alone. Suddenly, the bitch librarian, who was new that year to the schedule, starts bitching at me for making a mess. Unfortunately, I was still very shy at the time, and didn't talk back. She then made me clean the crap up, and came after me infront of my French teacher who I'd known for years. Very minor, but it still pisses me off to this day.