I work in an office tower. I go to a lot of meetings. I am lazy and don't hike the stairwells, and I have bad knees to boot.
Enough background.
So what drives me nuts is when you get to your floor, and somebody bowls you over by rushing in past you before you have a chance to get off. Elevator etiquette: Let people off before you get on, you friggin' moron.
Sheesh.
