If you are standing in front of an elevator waiting patiently for it to arrive after you have punched your destination button, please, do not rush into the elevator immediately it arrives without considering the others trying to exit.
Courtesy demands that you wait until all passengers have exited the elevator before you try to enter the elevator.
Bottom-line: Wherever you find an elevator, make it a habit to not rush aggressively into it before others exit. Being patient and allowing others to exit before you enter will benefit everyone. Correct?