I was at a youth pool skating contest for a contest series in Florida. Clive Dixon had showed up. He was a strong skater on the contest scene at that point, and was just coming back from breaking his wrist at a bigger am street contest 6-8 weeks prior. I was a little nervous going up against him, but he wasn't regarded as a transition skater so I thought I may have a shot at beating him. He dropped in to the shallow end, did a pretty aggressive frontside grind in the deep end, came back to the shallow end and popped up into a back disaster. Overturned the back disaster, shoulders got over rotated, and got pitched backwards to flat. He stands back up clutching his wrist, he had caught himself with that hand and completely rebroken the wrist so it was hanging at an angle. Threw his board on the deck, got himself out, shouted "GOD DAMMIT!" Focused his board with one big stomp and ran off to the pro shop.
I'm not sure if it qualifies for worst, but it certainly pumped me up.