In or Out?

What is proper door etiquette?

I'm not talking about, should a man hold the door open for a woman? Yes, he should by the way. It's good manners. Plus, as a woman, I deserve some perks :-) that's a different discussion though

Here's an example of what I'm talking about...one day I went down to the cafeteria for lunch. There are 2 double doors and 2 single doors flanking them. All the doors are glass, like retail stores. If you're exiting the cafeteria you have to PUSH the doors open into the corridor. So, I'm leaving the cafeteria, with my lunch to-go, and I chose the single door on the far right (kinda like being in the far right lane on the road), there is a man on the other side of the door who wants to come in. First of all, there's 5 other doors he could have used. Anyway, I push the door open and he steps in front of me to come in, like I should squish myself next to door and let him come in before I go out. I just looked at him and said, "are you kidding me?" He backed off to let me out but he didn't offer to hold the door open. That really ticked me off. Then I noticed that that very situation happens a lot more frequently than you think. And when you come to a door at the same time as someone on the other side of the door, who should go in/out first? Who has the right of way? I think it's the person who has to PUSH the door, not PULL the door. And if you have to PULL the door, should you do so and let the other person/people through or just stand aside and wait until the PUSHer(s) are through? And if I'm the PULLer and the PUSHer is a male, should I hold the door for him? Or when he comes through, should he wait and hold the door open for me? And if there is more than a one door or one set of doors, do you get to use any old door? Or do the rules of the road apply? You know, left and right traffic.

It's a trivial thing I know, but life is filled with trivial things.