My worst (and last..knock on wood) self-hookup occurred at Twanoh State park when I was 10 years old. Every year we would head down with various family members for a week long camp. At night, my little brother and I would fish for sand shark at the end of the mooring dock in the park. THERE ARE SOME DAMN BIG SHARKS IN HOOD CANAL!

We would catch bullhead for an hour, cut them in half to chum the water up, then started fishing the halves about 1 hour after dusk.
The water would be brimming with 4-7 foot sand sharks, and the were alot of fun to catch.
My basic setup was a steel cable leader to a tandem pair of 2/0 trebles. One one occasion I had about a six footer on the dock, carefully removing a treble from his mouth when he thrashed and hooked me with the other hook on the leader. Now I am in a big pickle with a thrashing, well hooked shark held down by one hand and my other hand hooked in my thumb with a barbed treble. My little brother was scared by the whole situation and couldnt help me remove the hook, so I begged him to keep the shark steady while I figured out what to do. In retrospect, the smartest thing to do would have been to cut the leader to stop the agitation from the shark, but we didnt think about that at the time. After we attracted some more shark into the area with my own blood spilling into the water for 5 minutes, we got the shark released and went back to camp to show Mom and Dad what had happened. I ended up going into a clinic in Belfair the next morning to have the hook removed. I still have a nice scar on my thumb from the thrashing shark.

Note to other fisherman, if you get hooked while a fish is one the line, Cut the line first! then deal with the hook!