I do stupid stuff too, but my best example of this is my husband.
I was upstairs folding laundry when he comes bounding in yelling “I cut myself!”
As per our usual joke, I said, “oh, what, do you need to go to the emergency room?”
To my surprise, he said yes. He had completely cut through the webbing between two of his fingers, severing some nerves, and requiring 12 stitches.
How did he do this you might ask?
Well, he got it into his head that since the ice cream in the container was REALLY HARD, a butter knife would work better to pry it out than a spoon.
When the ice cream resisted, he pushed HARDER (that was some really frozen stuff, right?)
Turns out, he was pushing the knife against the bottom of the carton, NOT the ice cream. Punched through the bottom, full strength, and straight through his own hand…
*face palm*
The ER staff was so amused they kept bringing new people in just to hear the story…
OUCH !