When Another Player is addressing the ball. There are only two things that every other player should be doing when a player is addressing the ball: standing absolutely still and watching the player hit. Movement is unacceptable. Talking is unacceptable. Fussing with equipment is unacceptable. Looking around is unacceptable. Stand still and watch the shot. If you can't render this simple courtesy, then you do not belong on a golf course.

You'd be very surprised how many people forget about this very basic rule.