I was working on a printing press to diagnose a problem and my thumb slipped and went through a gap between a rotating cam and staionary shaft about this big | | , my thumb was this big |........| before. After the incident I grab a shop rag and wrapped it up, fixed the problem and went to the clinic. I ripped the thumb nail off, split it open and fratured the tip. I needed 8 stitches and lost the nail, it lost some feeling as well. Thye most painful part was when they soaked my hand in ice water, I almost passed out.
Our rule is never put your finger where you would put your Willie Nelson.
I was welding once and not wearing gloves, but a wedding ring...using a MIG with flux core wire. a piece of slag landed on the ring and,

let me tell you, gold is an excellent conductor

it gave me a 2nd degree burn and hurt like a bastard.
Most of these injuries happened when I was young and dumb.
I was cutting a 4" PVC pipe hanging vertically, I was in an awkward position and using a hack saw. Instead of cutting it completely I decided to break it off...bad idea. When the pipe broke it hit me sqaure on the face and broke my front tooth.

The owners of the company happended to be right there and asked if I was ok, I said yes and told them I guess I'm pretty tough and can take a punch...I felt like Billybob for a few days.
I am older and much wiser now and I try to teach others about my past experiences, some will never learn.