I can tell AC from DC by feel, which means I've obviously experienced that a bit too much (and learned electronics back when vacuum tubes weren't vintage.)
I have a nice scar across the back of my hand from a protruding nail while doing demolition for my studio; it will help me remember the experience.
Probably the scariest was when doing a "festival-style" gig (aka lots of other peoples' equipment) about 25 years back. I went up to the mic to do backing vox and got a white flash of light and found myself standing back several feet (the lack of any bass at that point got others' attention.) So, as the show must go on, I wandered back up, gave myself several inches between my lips and the mic, but a sweat-soaked lock of hair swung down and hit the mic. Bang! At this point I'd had enough with singing and just tried to play my bass while plotting how to kill whoever set up the stage. The lead singer didn't quite understand what was going on, pulled his SM58
off of the stand during the next song, wandered over and put his arm around me. He understood then.
Turns out that whatever asshole owned the bass rig decided to cut off the ground prong, and the PA was probably on a different leg of the three-phase to the building. Or something.
Learned a lot that day.
The most helpful injury came on about my second gig ever; after standing a foot away from my rather ham-fisted drummer's crash cymbal all night, my left ear rang for three days. I decided, even in my addled youth, that this didn't bode well for my future, so I've worn earplugs religiously ever since. Now I'm pushing 50, and building a studio, and can still hear. Whew.