If you are accustomed to shooting firearms, you learn to squeeze the trigger, slowly at first and then more quickly as you gain expertise. However I found out the hard way, that you don't want to squeeze the trigger when operating a nail gun. Even though mine had safety features, I squeezed the trigger and resulted in a double tap. The first tap when into the wood as planned and the 2nd went into my finger. I found this to be most unpleasant. At least when I got to the emergency room, they didn't ask too many questions as to why I was there. The strange part was that the next finger that was just pinged by the nail took longer to heal as it apparently damaged a nerve, whereas I was most fortunate in that the finger impaled did not receive a hit to the bone or nerve.