When I was a kid, my mom had received a big, fancy electric can opener as a gift one year.
On the rear side of the unit were slots for a a two stage electric knife sharpener.
I looked at it and figured I could sharpen my ice skates in the knife sharpener if I could just get them into the slots. I eventually realized that if I took the cover off, I could access the spinning sharpening stones.
After learning how to defeat the safety switch, then running my skates back and forth over the spinning stones for several minutes, the motor blew out a puff of smoke and stopped dead.
The sharpening motors were only supposed to run for a few seconds at a time, and I had burned them out.
I quickly put everything back together and felt terribly a few days later when my mother couldn't use the opener/ sharpener any longer.
I carried this guilt for many years until I finally told my parents what I had done when I was a kid.
They just laughed and my mom mentioned that she hated the thing. It was so difficult to line up the cans properly, and it always left ragged edges on the cans and lids. She only kept it out on the counter because her sister, who came over everyday for coffee, was the person who gave it to her as a gift.