How to be polite in 2 seconds or less

Why do I always find myself in a position where the person in front of me refuses to hold the door open? Does it really take that much effort to just prop the door open for that extra second until I grab a hold of it? I should never assume someone is going to hold the door for me or else I end up with a door in my face. People just suck.

I don’t even know why I bother anymore.

I try to be the nice one and do the polite thing, but then someone goes ahead and on 2 separate occasions within a 3 minute time frame, just walks through the door letting the door swing close behind them. Were these people never taught any manners? How barbaric have we become? Is rudeness the new black, because someone never sent me that memo…which I guess makes sense.