So, here's something I recently experienced and thought I should discuss. In order for you to understand the scenario, I must first explain the setup of the environment. I was approaching the entryway of my school, where there is a large, covered patio at the front of the school, which is attached both to a parking lot and to a series of doors to the inside. These doors open to a small, carpeted "median" area, which then has another set of doors that open to the lobby of the school.
So I grabbed the handle of one of the doors in the first set of doors, swung it open, and did the characteristic half-turn that looked like it was a casual part of the door-opening but was actually a sly reconnaisance manuever I do to see if there's anyone behind me for whom I should be opening the door.
I saw someone approaching: A teacher; someone who I hadn't seen for a while, but who would probably still recognize me. She was a curious character, like most history teachers. Once I found her in a computer lab listening to Celtic Music, which as everyone knows, is something that nobody likes to reveal they listen to, but everyone actually listens to because it's so awesome.
Anyway, I saw her approaching, but she wasn't really that nearby. She was somewhere in the middle of the patio, which means she was about, say, twenty feet away. My question was, do I hold the door open and wait?
Now, there were several factors that went into this rapid-fire processing I had to do. I had to determine how fast she was going, how far away she was, what the impact would be on me if I were to hold the door open (Would I be late? Would I be standing there for half a minute like an idle fool?), and what the impact would be on her if I failed to hold it open (Did she recognize me? If she did, would she think I am a jerk?).
After weighing all of these factors, I decided, without wasting too much time, that it wouldn't make sense for me to hold it open. She was too far away.
So, as soon as I let go, and started walking into the "median area" between the first doors and the doors that open to the lobby, I immediately felt I had made the wrong decision. To turn around and hold the door open now would be suicidal. I had to come up with another plan. And fast.
Something came to me.
I walked a bit more slowly across the "median area" to the second doors, pushed one open, slowly, and stood there for a second, fudging with my pocket, which happened to be empty. By that time, she'd reached the first set of doors, and there it was. A beautifully simple solution. I held open the second set of doors, because she was well within the buffer distance. I avoided looking like a jerk and still held on to my dignity by not standing at the door for an unnecessarily long time.