DOOR HOLDING. One of the most oft confusing and awkward sociological messes to ever burden mankind.
The way you even go about this says tons about the type of person you are. Are you being a kind soul trying to give another person a little added convienience during the day, or are you a douchebag, doomed to obliviously burden others with your so called "kindness" which is anything but.
Pay attention here. If the person you are so generously holding the door for feels obligated to change from a casual stroll to a panicked run to grab the open door, you have just COMPLETELY FAILED in your little act of kindness. Not only that, but you have just utterly reversed the situation - and now THEY are going out of their way to not inconvienience YOU. Believe me when I say this to all of you that continue to hold open doors for others. We, the potential door openers, would much rather open the god damn door ourselves then be forced to run up and grab it.
Now, the one obvious variable in all of this is, of course, is the distance from the door the other person is at when you decide to hold the door or not. If the distance between you and the person behind you is anything more than 5 feet away (about 1.5 meters for you dirty foriegners), simply let the door go and be on your way.

If you enjoy obliviously holding a door at up to 20 feet away from another person headed your way, you are in fact a douchebag, and you don't even know it.
You're all welcome for me bringing this to your attention and lack of common sense.
LOL BYE.