This may not be the dumb a$$ winner that I have pulled (there are SO many to pick from) but I tried to take the grinding wheel off a paddle swich angle grinder while it was plugged in. While using my hand to counter turn the wheel I hit the paddle swich and ground a real nasty groove in 4 fingers.
Not a shop item but a real dumb move I made many years ago. While slap happy drunk (1970s kind of drunk

)I picked up a rock that had just rolled out of a large camp fire. My hand was totaly out of order for weeks. BTW. Rock seared hand smells like steak.
Sometimes you have to learn by your own bad moves but it sure is easer to learn by watching others mess up.
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http://vimeo.com/29896988
“Those that can make you believe in absurdities can make you commit atrocities.” Voltaire.
"There is grandeur in this view of life...." Darwin.
The mountains are calling and I must go.
“The earth has music for those who listen”
Shakespeare.
You Matter.
(Until you multiply yourself times the speed of light squared. Then you Energy)
“We’ve got lots of theories, we just don’t have the evidence’.