Elevators

PET PEEVE: I cannot stand when I'm waiting for an elevator, I've pushed the button, and someone else also needs to use the elevator but has to press the already-pushed button anyway.

Am I inadequate with pushing buttons? If the button is already lit, doesn't that mean that it's going to go to that destination, or do they need that deep assurance?

Constantly, I am going up and down elevators at my job. I cannot stand business men and women who continuously do this. As you can tell, I become extremely frustrated; maybe I take a bit far, but it really hits my nerves. Hopefully I don't snap someday.