That's just straight-up cultural norms; just because it's customary in the US (and maybe even then only in certain areas), doesn't mean it's the same everywhere

That's just straight-up cultural norms; just because it's customary in the US (and maybe even then only in certain areas), doesn't mean it's the same everywhere. To wit: a former coworker of mine was Romanian, and a rather tall fellow. Whenever he wanted to talk about something, he'd sidle up within about a foot and start chatting. This was unnerving because he was probably 6'4 or 6'5, and suddenly he was all up in my business--once I realized that it was just different norms, I was fine with it.