In my opinion the worst behavior is the 6 and 8 and under parents. When the kid needs reassurance after a loss or just a hug from their parents I've seen them get yelled at for not doing this or that. Last year I actually heard a father tell his son that he didn't deserve the 4th place medal because of how he wrestled - this was 6 and under!

I've often thought that someone should tape these parents and how they act at matside. Anonymously send the tape to them to view when things have calmed down. Maybe they will change their ways!