A community of strangers
If you go to a small town, people will often look up at you when you walk into a public place--such as a restaurant--to see if you're no stranger.
In contrast, if you live in a large suburb (like the one I'm from) people often hardly acknowledge you.
This gets to the crux of the isolation that so many often feel. Because if all you see is a sea of distant strangers when you look around you, it's going to be hard to feel like you're part of a community who cares.
Alas. I don't think the solution is to live in a smaller town or to make more friends out of strangers (although that couldn't hurt).
What I think works is acknowledging that even though everyone seems like a stranger, they're also a neighbor, in that they share a common space. (Often for the same reasons.)
Choosing to see the little things that make us similar might be all that it takes to begin to see how much we're mostly a community of potential confidants, companions, and friends.