My stupid thing that happens to me is I use one of those mandolin vegetable slicers. I know you need to use the special pusher to keep your fingers safe. I do it most times, but every so often, I get impatient and trust that I will be careful. Am I careful? NOOOOOOOO. Do I cut my finger(s)? YESSSSSSSSSSSSSS. Do I learn, NOOOOOOOOOOOOO.
Insanity is keep doing the same thing under the same conditions and expecting a different outcome.