there are so many stories of my stupidity, but here are a few:
-I tried to rush the cleaning of a vintage razor by using a belt grinder...and made permanent uneven areas on the blade.
-Rushing cutting a pivot pin and hitting the blade by accident with a hammer...breaking it of course!
-I was doing the final polishing on a blade restore, and let the edge come up slightly while working. It was just a hair but enough to catch my finger and leave a wicked cut! My wife had a kitten when she saw that one...