I got a kick out of the white guy with big fluffy dredlocks in "Children of Men", who would hold his gun sideways while pointing it at someone if he wasn't about to fire but was just threatening or running toward him/her, and then flipped it upright to fire (and then back again).

(There was one exception, and in that particular case, he was firing sideways without even looking toward his target a few feet away; instead he was staring at the other guy he wanted to intimidate and scare for a while before killing.)