We'd all gotten tickets off fandango, but we had to exchange our printed slips for actual tickets before we were let in. The girl at the ticket counter took one look at our group, saw the guys chatting about Kirk and Spock and whatnot, and just pressed her palms against her eyes and sat that way for the next half a minute or so while one member of our group was trying to get his slip exchanged. She just ignored him while she sat there for about thirty seconds before deciding to actually help him.
Even after that, in between people she would roll her eyes, shake her head, and make little "shoot me" motions as each next person stepped up online. It wasn't even to a coworker, it was just her acting rude for the sake of being rude.
It was especially bizarre since, 1) we weren't being loud, and 2) there were only about ten of us, and we were the only people on line (we showed up a few minutes late), so it wasn't as though she were dealing with anyone being obnoxious or was going through a huge procession of people. She just decided to be rude to us for no reason, or because we were just a bunch of geeks showing up to a movie.