I had built a 28'x40' garage and was insulating the ceiling. I borrowed a swing hammer stapler from my Dad. Being on a step ladder, stapler in one hand and trying to hold the insulation up with the other, I wasn't very stable. I hit my thumb squarely on the thumbnail! I saw stars! An hour later, I hit it again driving a staple through the end of my thumb. Another hour later, I placed the stapler on top of the ladder to move it. Holding the two legs of the ladder with both thumbs resting on top of a step, you guessed it......the stapler fell off the top of the ladder and landed right on the same thumb! I shut the lights off, closed the doors and went into the house.