Some people at my work are unfamiliar with widespread social conventions. Let's review.
1. When entering an elevator, don't immediately turn around and stop as soon as you cross the threshhold, especially if there are ten other people behind you. Move to the back of the elevator so everyone else doesn't have to walk around you. If you have to get off at a nearby floor, get on last so that you don't have to push everyone else out of the way. Finally, if an elevator is crowded you may need to stand close to another person; however, when the elevator empties and it's just you and me left, you don't need to keep standing directly next to me. Thanks.
2. One easy way to know if a conversation is over is when both you and the other person say "goodbye" or "see you later". You may be completely insane if you often find yourself saying things like this:
"Ok, great then, see you later, how's it going?"
Normally this will be met with a blank stare, because I won't be able to comprehend what just happened. Are we done with the conversation, or are we still in the middle of it? Are you starting a whole new conversation with my retreating back?
3. Don't turn off the lights just because you are leaving the room. If there are still a half-dozen people inside, they will probably want the lights to remain on. One way to determine if there are still people in the room other than yourself is to simply remove your head from your butt and look around.