Thomas B. Marlow returns with the latest installment of his Rules of Everyday Life -
Rule 4: On Going Through Doors
When presented with an entryway, there are several factors one must consider before proceeding through one door or another.
Number of doors:
1 - Go through this door. Wait for anybody coming through from the opposite direction, and hold it for anybody following you.
2 - Go through the door to the right.
3 - Go through the door to the right. The middle door should not be used except in the case of fire, or some other emergency that legitimately calls for mass movement. As you pass through the door, silently curse the architect for placing three doors in the passageway.
4 - Go through either of the two doors on the right, but preferably the one farthest to the right.
5 - Seriously? Either of the two doors on the right, again preferring the one farthest to the right. Curse the architect out loud.
6 - Go through any of the three doors on the right, with the outermost doors most preferable.
7 - Do not enter this building.
8 - Go through any of the four doors on the right. Pretend that these doors are numbered 1-4 with the number increasing as you move to the right. The best doors to use are (in order of best to worst) 4,2,3,1.
9+ - Do not enter this building.
General Guidelines -
1. Obviously, the door on the right of the structure are most preferable, but if a stranger is holding a door for you, go through that one. That's right, even if it is on the left. Sometimes, being polite is more important than strict adherence to the rules.* If a friend tries to hold a left door for you, look at them and say, "Hey! NO! We go through the correct door, crazy!"
2. Holding doors for people behind you is recommended. It is mandatory if you can tell the person behind you is pregnant or has an injury (I once saw a friend let a theatre door slam on a girl with a broken leg. She probably doesn't care for Thomas B. Marlow's rules at all.) In the case that there is an able-bodied person far enough behind you so that you'd have to wait a bit holding the door for them, and they don't make an effort to quicken their pace as to reach the door in a more timely fashion, let it go.
3. Do not hold revolving doors. Do not repeatedly go around in revolving doors. Act like you have been in a revolving door before.
*Not always. For example, regarding pie seasonality: adherence to the rules > politeness.