This peeve is aimed at those working in the same office block as me, although I suspect it's fairly common in all offices. To those who are using the lifts at the same time as me: don't press the "doors close" button!
The doors close automatically. If no-one has called the lift from a particular floor they will close swiftly. If someone has pressed for a lift, the doors stay open slightly longer to give the person time to get on. There are four lifts in the area I use and it's not always possible to tell which lift will be stopping.
I've several times walked towards a lift, only for the doors to be closed before I could enter. Very often the doors have started to close as I enter, and I spot someone standing there with their finger on the "close" button. Why do these people bother? They save perhaps ten seconds maximum. Are they so keen to get back to work?