Who was the worst teacher you've ever had?

Hard to choose one worst one, among several really bad ones. Starting with Mr. Fielding in the 5th grade, who was fixated on matters not related to actual school subjects. His main thing was talking about his time in the Foreign Legion or something, and insisting we learn all the words to the song "Green Berets". He made us march around the playground singing it, to the amusement and derision of the other kids. It's pretty funny, on reflection.