In my office building, the lights above the elevator doors turn red if the elevator is going down and white if the elevator is going up. Everyone knows this.
So on the way up today, just as the (clearly white-lit) doors were closing, someone stuck their arm in and asked if the elevator was going down. The guy already in the elevator with me barked that the elevator was going up.
Then, as if the sharp tone wasn't enough, he started to sigh and roll his eyes and say 'God. Really.' Over and over again. When I made accidental eye contact with him, he said (without a hint of irony): I just lost five seconds because of that.
I know now that the proper response was: you've already lost another twenty bitching about it. Move on. Unfortunately, I'm not that quick.
This did teach me a little lesson. The next time I find myself infuriated over a momentary delay, I should make a concerted effort to remain patient and calm. Because otherwise I would be a gigantic douchebag.