one day last year I was in the gym and went to the lat pulldown machine in the middle of my workout. someone had it on 200 lbs or something, so I pulled the pin out of the weight stack, and the entire attachment fell on the back of my head. this was a really heavy metal attachment, must have been like 20-30 lbs fell on my head. I got really dizzy for ~30 seconds and had a big bump on my head, but that was somehow all that happened.
to this day, I'm kind of scared and cautious whenever I change the weight on those machines.
Went underprepared into a mountain somewhere in the caucasus. Didn't have the right shoes, no sticks, and didn't expect big, sharp rocks hidden under a thin layer of snow. If I had injured my ankles(very possible) I would have had to crawl back to civilisation. There would have been no rescue. Also some local told us that the hike was very easy. In the end I let my companion finish the hardest part of the hike himself and waited for him, and got back without injury.
Another time I was on a short hike with some lowland people in Kyrgystan, and when the weather started to turn, and snow flurries started to appear. I almost begged them to turn around, we were at 3500 metres above sea level, and I knew enough to not risk anything. They laughed and went on. They thought that there was no danger, and that bothing could happen. We did turn back early at least, and 2 to 3 hours later the flurries turned into a storm, that would have been very dangerous if we had still been outside, especially for people with 0 hiking experience(like my two compagnions). Those two never realized the danger we were in and I hope they never go on a mountain again.
I did a lot of dangerous mountaineering stunts while foraging for mushrooms as a child. Falling to your death is a common end around here for people who collect mushrooms, so I am [n good company. Did teach me how to navigate horrible terrain tough.