What the fuck ever happened to that whole "cup of sugar" thing?

Remember that time a couple months ago when I jumped across to our neighbor's balcony to let her into her apartment because she got locked out? We never saw her again after that. One day we came home and the door was wide open and all her shit was gone. Also, there was a new refrigerator sitting outside the door. We assumed she had moved because it required less effort on our part than if she had been robbed. By a Sears delivery person, apparently.

Anyway, some new people moved in a couple days ago. Most people find out they have new neighbors through a very brief conversation with a group of strangers carrying a sofa up some stairs, which is convenient because it has a built-in escape route. That conversation goes exactly like this:

You: "Hi, I'm _____. It's blatantly obvious you're moving in, so I'm trying to find something less clichéd to say."
New neighbor: "Nice to meet you. I'm carrying something really fucking heavy, so I don't really want to talk to you right now."
You: "I'd offer to help, but I'm afraid you'll accept and then I'll also have to carry heavy shit, and one beer is so not worth it. See you later."

This is the only conversation you're obligated to have with them, ever. Then you're free to ignore each other until one of you moves out. This is not how we met our new neighbors. Instead, we go out to our balcony, and on the very same balcony I jumped across to, we see a woman and her two daughters. The woman looks pretty pissed, and is alternately trying to talk to someone on the phone and muttering about how the hell this even happened. She tells us that she had followed her daughters onto the balcony, shut the door behind them, and then found it locked—even though it only locks from the inside. Even better, the deadbolt on the front door was locked, too. I'm pretty sure this apartment is haunted by the ghost of Houdini.

Of course, this story ends with a man we'd never met before coming through our apartment, jumping across to the other balcony, and using a piece of wire to break into his own apartment. Because this is the only way we can meet our neighbors.