How about when someone dismisses your feelings or opinion as being unimportant after they lableled you a "hot head???" back atcha bro!And hot-headed people making a big deal of everything.
Or what about the one who comes and shoves his way into the line and then says .... I only have one item.Finally getting away to do some grocery shopping...and then round the corner to find two chatterboxes clucking away with each other, blocking the flow of shopping cart traffic...and nobody says anything! (I usually do...something like "Honk-honk!"