I've got a few of these... mostly when I was in Kung Fu, I made some pretty dumb mistakes that got me busted up.
The first time, I was sparring with this one guy, who was actually the same size as me, so we could be a bit rougher with one another. We both threw kicks at the same time, shins collided, and his was the victor. Meanwhile, I had a grapefruit-sized lump on my shin that took weeks of Rest Ice, Compression and Elevation (and ibuprofen!) to heal.
Second time, I was sparring another bigger guy, dude was about half a foot taller than me. I'm trying to get inside his range because he had freakishly long arms. Meanwhile, he's throwing a punch aimed for my stomach. But because I was trying to be slick, I ducked my head, so the fist landed square on my nose. It bled for a while, and been crooked ever since.
Finally, the last one was the most idiotic. We'd been learning an interesting shuffle-step that I was trying to work into a ridge hand. So I did it, and for the first few fractions of a second, it felt great. Everything felt *right* about that strike. Then I rolled my ankle and had to take a few weeks of downtime while it healed. A few weeks later, the kung fu school closed down due to rent and conflicts with the property owner. So it goes.
