As an aside, there are a series of fascinating studies on the way different nationalities make friends (can't find the articles right now, but will post later if someone is interested). One of them, briefly, highlighted the differences in "greetings". Americans tended to say hello when walking by someone to even "marginal" friends (people they didn't really know that well), while those from one of the other cultures studied (I think an African country, maybe also an Asian one?), only greeted those they felt close to. This, obviously, caused a LOT of confusion as the Americans didn't use the greeting to indicate deepening of friendship, but the international students did.
We do a lot of work with pastoral care of international students in my department, and it's interesting for me to see the parallels to what *I* go through, and it helps me keep perspective sometimes.