Worst physical pain ever?

Probably have to be some burn that I can't think of right now... I can't remember any of the semi-major things that happened to me hurting... I tore off a large amount of skin and flesh (think meat) from my knee at Disney World, but I just stared at it and wondered why it didn't start bleeding immediately. I also had my big toenail torn off, but I was freaking out too much to notice any pain I think. I figure shock numbs pain.

How did you tear off your skin and flesh?