[Bartweiss]

I think the other side of this is that using the USA as the far end of the scale is a mistake. A quick trip through much of Latin America, or for that matter the US Midwest, makes clear that the UK and coastal USA still do quite a bit less talking to strangers than other cultures. And by that standard, the stereotypically extroverted parts of Europe (e.g. Italy) are downright reserved.

For some reason, I do find the US standard more facile than either of the poles. Taciturn cultures like the Finns have obvious authenticity because people talk for reasons, but very high interaction cultures have their own sort of sincerity: people talking idly because they're enjoying the act of conversation. Trading a few sentences as pure courtesy misses both marks, and often feels more draining than a much longer conversation.

(Now I wonder if this is tied to US tipping and sales cultures, since "act blandly nice" becomes an important transaction for a lot of people. Obviously it's not the whole story, but I do find even UK conversation rather different than the US pattern.)