zeogold: Cool! You can hit door-to-door salesmen!
timppu: At least the stupid ones that stay too close to the door!
...who said anything about hitting them with the door?
timppu: I've seen it also in e.g. Thailand. In cities people may even have their apartment door wide open all the time, and a neighbour just drops by to chit-chat.
Having your door wide open? That's even wilder. You'd get robbed here like that.
timppu: About America, is it possibly also a regional thing? Somehow I've gotten a feeling that in bigger cities people don't necessarily know their neighbours all that well. Maybe it is all those movies and TV series where Seinfeld or Frasier is surprised someone lives in the same floor as him, or something. Well, ok. Kramer always crashes into Seinfeld's apartment and eats from his refrigerator like it was nothing...
It does somewhat have to do with region, but not always with big cities. I mean, there's still the infamous "Southern hospitality" thing in the South where there are still people who don't even lock their doors. Even with that, though, we're still a notably "nicer" country than a lot of European ones, as it's common here for people to casually chat it up with strangers, which I've heard is a no-no in a lot of European places.
It may have something to do with size as well. We apparently used to be a friendlier/more trusting society back a few decades ago, as shown by the tales of people not locking their doors, knowing their neighbors, and the TV tropes of people leaving their car keys in the sun visor.