My apartment is about 5 feet from one neighbor on one side, and 5 feet on the other side.
This means that during spring and fall we hear each others' conversations because all our windows are open to enjoy the beautiful weather. This means that while I've only talked to them once, I know the names of the kids who live next door, and I know that their boy, who is a little older than Kiddo is a whiner. And his dad has no patience with that.
But, they know that we have to convince our oldest to use the potty any time she goes, and that she doesn't like to pull up her underwear.
This also means that my daughter can look out her window and watch our neighbor's parties in their backyard, with them 10 feet away.
I suppose we learn these sorts of things about our neighbors in the individual house neighborhoods of suburbia, but there you can pretend that you have privacy. Here there is no illusion.
Is that why we don't talk to each other? Because we already know what's going on in their living room, we don't need to visit?
