When elevator etiquette is completely lost, our civilization will truly be beyond repair. Period. There are a few simple rules:
1. Ladies first...
2. ...Unless the lady looks like she will be pissed by a showing of chivalry, AND you are brave enough to not worry about looking like a monumental jerk... in which case, ladies second.
3. As between ladies, the first to arrive goes in first and leaves first. Concurrent arrival of ladies = oldest in first and out first. Concurrent arrival of ladies of the same age = anyone's guess.
4. Sticketh not thy hand between closing elevator doors so that you don't have to wait for the next car. Otherwise, you've told the rest of us in the car - the rest of us who had to wait in the first instance and then had to wait again for your arrival - that it's more important for us to wait another 15 seconds than it was for you to just wait your turn. In other words, you're a jerk, and I will spend the entire ride daydreaming about your phalanges getting caught in the closing doors.
5. If you're in a crowded elevator and talking on the phone, don't be surprised to have said phone jammed up your backside. Chances are, it will have fewer bars there. Can you hear me now?
6. As people disembark from the elevator car, spread out so that the space between the remaining folks is relatively equal. Do it as a matter of course. Don't wait for someone else to do it. Don't make someone else do it, just because you want to plant your flag in the one square foot of elevator space you've claimed.
7. Don't whistle. Don't hum. Don't sing. And for god's sake, don't blow your nose. If it can't wait until you get out of the elevator, chances are you shouldn't be there in the first instance.
8. If I'm running toward the elevator, at least make the show of trying to hold the door open. If you're in there, jamming your finger on the button to close the door, I'll know about it. And I'll remember it. And some day, perhaps in a galaxy far, far away, I'll exact my revenge.