Walls keep you from seeing things. They help make things less real. Sure, maybe you hear loud, sharp noises outside some nights. But it's easy to tell yourself that those aren't gunshots, that there's no need to call the police, no need to even worry. It's probably just a car backfiring. Sure. Or a kid with fireworks. There might be loud wailing or screams coming from the apartment upstairs, but you don't know that the drunken neighbor is beating his wife with a rolling pin again. It's not really any of your business, and they're always fighting, and the man is scary, besides. Yeah, you know that there are cars coming and going at all hours from your neighbor's place, and that the crowd there isn't exactly the most upright-looking bunch, but you haven't seen him dealing drugs. Not even to the kids you see going over there sometimes. It's easier and safer to shut the door, be quiet, and turn up the TV. We're ostriches and the whole world is sand.