When my wife and I moved to New York City in 2001, recently graduated from college and newly wed, we were eager to find friends. We knew nearly no one but were sure we’d soon find a fun-loving group like the 20- and 30-something New Yorkers who spontaneously dropped in on one another on TV shows like Seinfeld and Friends.

We hatched a plan. After moving into our Midtown Manhattan apartment, we invited all the neighbors over for drinks by placing Kinko’s-printed quarter-sheets into everyone’s mailboxes. Then, we waited for our versions of Chandler, Kramer, and Elaine to show up. But they didn’t. In fact, no one did. As the ice in the cooler melted and the guacamole browned, not a single person among 100 apartments stopped by. Not. One. Person.

Recalling that episode now, we sound embarrassingly naïve. We didn’t realize