Just my two cents.

This isn’t really a post, I just wanted to respond to a friend’s facebook status, but without leaving a paragraph no one would read…so I’ll put it here…where it can more easily be not read.

(The post was over which countries are more polite, with assertions that Americans are more polite than Europeans.)

It’s one of my inconsistencies that I think such broad generalizations are inherently pretty useless (no nation is that homogeneous) yet find myself interested in them and making them myself.  So I won’t pretend to be an expert, but having traveled in 39 countries I can offer my impression.
With regards to politeness, the US varies so immensely it is almost obscene (see: political discourse, racism, sports fans) but if I put my rose-tinted glasses of optimism on, I would rank us as near the top for politeness in interactions with strangers.  We smile and nod on the street, hold doors, talk to waiters and cashiers, and ask each other how it’s going.  (That last one in particular amuses people here, particularly on the phone.)

(I would say this politeness is more common in smaller communities, since cities are more of a nationality in themselves, regardless of which country they happen to be in, but that’s another topic.)

So I would say America does very well…but only compared to other developed countries.  (I have not been to Japan.)  I have yet to find a single developing country that doesn’t kick the holy crap out of the US when it comes to hospitality and manners towards strangers*.

(* Caveat that this exempts a few highly-touristed zones, where the unscrupulous will try and rip you off, though even then I can only think of one country where I felt this way.)
From Guatemala to Zambiato Nepal, the level of openness and friendliness towards strangers beggars our behavior in the West.  Of course it is not universal, there are assholes in every land, but I think one learns a lot about hospitality, priorities, and humanity from traveling in undeveloped countries.

Which reminds me of one image that continues to amaze me.  In this secondhand anecdote it was in Kenya.  If someone gets on a bus to find it empty but for one other person, they will go sit next to that person, to talk.  I just love that.

My two cents.