A good friend, actually my across the street neighbor, both ripped their shoulder out of its socket resulting in surgery for both. It was not a gentle experience.
My friend worked for the railroad and jumped off of a train and held on too long. My neighbor was drunk and climbing down his boat ladder slipped and his arm jammed in the steps. Super ouch, but I'm sure he was well lubricated when it happened, but didn't have use of the arm for a pretty good while.