National Idiosyncrasies

...is a topic different from AmericanCulturalAssumption, but it seems to be discussed mostly under the codename of AmericanCulturalAssumption.

From the Merriam-Webster on-line dictionary - an individualizing characteristic or quality, although contemporary usage tends to use it as an eccentricity. -- RobertField

I don't know about [the "Cultural Assumption" part]. I'd classify something like SwedesStandTwoFeetAway? as a NationalIdiosyncrasy?, since it is not an assumption, but a habit of the Swedes (and others, as found in personal space studies).

Here's my share of cultural assumptions, in no particular order:

In Poland, the average mood of a citizen I describe as gloomy-to-neutral. That's what you see in public transportation, at least. Not that it excludes people having fun, but you get a rough idea. My Dad likes it each time he goes to U.S. that people smile at each other. So in Poland, he smiles at people too, and this seems fine, maybe just odd to some.

He also used to visit Switzerland once or twice a year. In his smiley mood, he was smiling to everybody. Apparently women in there countryside can get offended at that, and he ended being loudly referred to as a pervert (to say at least). He tries to constrain his smiley mood while being there from that time on. This was in Obwalden Kanton, in german-speaking part, so probably in other parts it might be different.

I find this astounding - smiling at people gets one tagged a pervert??!! Someone send the Swiss a few kilos of Valium.... -- PeteHardie

Ah yes, I'm from Poland, but I try to maintain a healthy distance in my point of view over all cultures ;-).

[I hope to extend this.]