Everyone makes mistakes. A key with firearms is the old, make sure the barrel is pointing in a safe direction especially if there is a round in the chamber.

I learned never to try to move the hammer to half cock on a rifle while walking or running after game. ie hold the hammer, pull the trigger lightly to allow the hammer to drop to the 'safe' half cock position. Easy when still but easy to fire off the rifle if jogging after game. Again my rifle was angled well up into the sky so the bullet went off safely. But got a bad reception from the other hunters in front of me who jumped in fright. Everyone makes mistakes. Good to make sure they are made safely though.