In 1853, Elisha Otis installed the first public elevator in a 6-story department store in New York City. I can guarantee you that the first time it was used, some asshole jumped on right before the doors closed and hit "2".
Despite 158 years of practice, it appears that a sizable portion of the population still has problems with Basic Elevator Etiquette. Let's review.
1. People get off first. Then you can get on.
The door opens. There is an elevator with people in it. Do you (a) Try and shove yourself on because goddammit I GOTTA GET ON THIS ELEVATOR NO MATTER WHAT or (b) Wait for the people inside to de-elevator? If you chose (b), you get a Gold Star and you're a cool person. If you chose (a), you're just another asshole, one of the millions.
Seriously, this isn't hard: EVERYONE OUT FIRST, THEN EVERYONE ON.
2. Doors closing? You don't get on.
As soon as the doors begin to close, even if it's just the slightest fraction of an inch, that elevator is now closed to new passengers. We do not (a) thrust our hand between the doors to make them open again, (b) frantically push the button, or (c) Say "Hold that elevator!" No. Once the doors start to close, that elevator's dance card is full. You are not on it. There will be another elevator soon. If it's an emergency and the building is on fire, you shouldn't be taking the elevator anyway.
3. The Two-Floor Down Rule
If you get on an elevator that is located anywhere near the stairs and take it down one or two floors and you are physically capable of descending a flight of stairs, you are a lazy bag of lard and you need to get some exercise, fatty.
4. No hold and talk
I can't believe I even have to say this, and I wouldn't believe it happens if I hadn't seen it myself, but you do not hold the door open so you can continue chatting with your pal or coworker outside the elevator. I mean, Jesus Christ. You cannot be serious with that shit.
Also, if you absolutely HAVE to make a joke about how often the elevator is stopping or some other zany elevator-type humor, go ahead, but just one and also think "Why am I doing this? It's not that funny." But hey, I get that there are Silence Haters who have to fill up every second with the noise of their own blathering and that's fine.
As long as we're talking elevators, two other things: (1) This fascinating New Yorker article about a guy who got trapped on an elevator for a whole weekend and also elevators in general is so worth reading that you're cheating yourself every second of your life that passes without you having read it; and (2) This guy is my hero: