Getting hit on the funny bone is no joke. This one time I was sparring in karate and my opponent goes to roundhouse me so I go to block it, but he ends up kicking me on the funny bone and like my arm was just screwed. It hurt him too but my arm just died, rush of pins and needles and pain and numbness. Forget getting a dead arm, that **** is fine after a few minutes but this was like, I couldn't even use it properly after I got hit for the rest of the evening. Whoever came up with the term 'funny bone' is a sadistic mother****er.
But my worst injury ever is probably when I simultaneously dislocated and broke my elbow from jumping off the monkey bars as a kid. I couldn't feel any pain at the time but I remember screaming for a teacher for ages on end. There was a period after the operation where the elbow joint would flare up while I was punching with my arm but thankfully that doesn't happen to me anymore and while that arm will never ever be able to fully straighten out again, it has healed well.