I once thought all people were equally capable and part of the same species. It's the dumbest because unlike a lot of other mistakes like blowing up a propane BBQ in my face, there was absolutely no evidence to support it other than the say so of people who were clearly hostile to me. The BBQ had a flame-out, I opened the door and relit and was greeted with a loud womp and hair sindging heat. I expected a safety valve, though to be fair the product literature said it had one, but otherwise pretty dumb.