8. When Professor McGonagall Got All Sneaky
"A week after Fred and George's departure, Harry witnessed Professor McGonagall walking right past Peeves, who was determinedly loosening a crystal chandelier, and could have sworn he heard her tell the poltergeist out of the corner of her mouth, "It unscrews the other way.""
Book: Harry Potter And The Order Of The Phoenix It's pretty fair to say that everyone hated Professor Umbridge significantly more than they even did Voldemort. She was the reason that all mandrakes cried. Thank you Professor McGonagall, for turning your back on the institution and helping Peeves to cause mayhem.