City neighbors

inspired by Stolie's post today
So, why is it that cityfolk don't know their neighbors, even though they live so close to each other? I propose that it is precisely because they live so close to each other that they CAN'T know too much about one another. Because they live in such close physical proximity, they can't allow themselves to know each other intimately as well.
I am friendly with lots of people in my building, but I wouldn't call any of my neighbors close friends. Also, I live in a building with fewer than 20 units. My friends who live in huge highrises know even fewer of their neighbors by name than I do. Now, I do live in the Midwest, so we tend to be a friendlier bunch than, say, New Yorkers. Even so, there's a distance that most cityfolk like to keep. Maybe those who live far away from each other (countryfolk) crave the attention of their neighbors, and so seek it.
I'm not anxious to hear more details of my neighbors' lives than I already do!