I have a few from days as a mechanic.
Only one proper one from the Cobra, My original quick bolts used to be big wood bolts, they had domed caps with no slot for a screwdriver or allen key,they did have a square molded into the underside to bite into the wood. To get them to sit flush on the quick jacks I had to remove the square piece from under the head.
I was doing this on a bench grinder, well I was pushing a little too hard and teh bolt caught the grinder and was ripped from my grasp.
Well my fingers did not go into teh grinder (I am sure you are all thinking that) but the threaded end of the bolt whacked the back of my third finger (not sure what that one is called) and it now has a scare that is earily like a bolt thread, and yes I did loose the nail.
Doesnt look like much but at the time it hurt alot.
Now for car injuries whilst being a mechanic.
Back in my 4th year as an apprentice I was working on a 323i Beamer (early 80's version) and tightening a hose clamp from underneath, I had teh car on a hoist and could only fit one hand through the small gap, I was using my left hand (I dont know why now as I am right handed) So I was pushing with moderate force as well as turning to keep the screwdriver engaged in the slot, well teh screwdriver slipped and my hand pushed up into the tight area, and in doing so the back of my hand scrapped over the tag end of another hose clamp, ripping the back of my hand open.
That took 6 stitches to close up.
Then I was replacing a ball joint in a VC Commonwhore, well instead of doing it properly I tried to take a short cut by not removing the lower control arm and using a press.
I got the old one out no worries then chocked the control arm so it would not go up, I placed the ball joint in its hole and found a socket that cupped the edge of ball joint.
Holding teh socket in my left hand I proceeded to whack the socket with a FBH, well inevitably the hammer missed the socket after a few blows (I was swinging hard as confidence was high I was hitting the target) My finger became the target and when hitting a finger that is between a hammer face and a control arm, let me tell you the finger is the first thing to give.
I hit it that hard that the finger joint "popped" out the side of my finger.
That finger gets very sore in cold weather now.