I'm sure that most of you (if not all) have been in a situation where you are in an elevator, the doors are closed and you are ready to enjoy your trip. And then somebody from outside pushes the button, the doors open up again and the atmosphere is ruined. Happens to me all the time! I think that's utmost irritating! Pushing the button is quite ok if the door is half open and still acceptable if the gap is from 30 cm to 40 cm. Understandable but not acceptable if the gap is 20 cm or less. But definitely not acceptable or understandable if the doors are already closed. Then you just have to take the next elevator. And still a couple of tips: hats off if there are ladies in the elevator, and don't touch up other peoples' butts!