Among Europeans at least, there’s always been the concern that our American perky cheer is fake. The smiles inauthentic. Eastern Europeans especially. I’ve spend a lot of time in the region, one time a guy I met in Belarus sort of watched me for a while in our social group before declaring “Bill is ok, he only smiles when he means it!”. A German friend was with me in DC when I said hi to a stranger on the street, he said that would never happen in Germany. But yeah, I do think our friendliness also gives them license to be the same. I live in Kenya now, I find that in public they have a similar stony reserve to the Slavs, but can be ‘broken’ quickly with friendliness and are generally deeply kind. Both the reserve and the kindness (and their impressive stoicism) probably come from growing up in a society that beats them down in countless ways.