There is an assumption in this thread that America has a unified culture that marks us as distinctly American. I would contend against this idea and say that even within America, we only have sub cultures without a meta-culture (though the sub-cultures are different from other world cultures, thus Americans as a whole appear different).
For instance, spend time in Dallas, TX, Abilene, TX, a small town in Missouri, a small town in Washington, Los Angeles, CA, and New York, New York and you will experience multiple cultures that are greatly distinct from each other.
For instance, name an American language, cuisine, music style, etc. Fact is, every dialect of English found in America, every type of food, every type of music, are parts of American sub-culture...but there is no unifying factor in American culture. I love cajun food because of the spices, but most people in the Northeastern United States will hate it because it's too spicy (and apparently the only spice they're aware of in New England is ketchup). A meal in the midwest will gross out someone from the West Coast. The accents of someone from southwest Louisiana or northern Alabama are almost unrecognizable to someone from Boston or Maine.
It used to be said that there was an underlying ethos that united Americans, one of the first cultures built upon a unifying idea rather than language or any other cultural traits; but we don't even have that anymore.
If anything, there is no such thing as an American culture; just multiple cultures unified by a government. Thus, what many "foreigners" (such a subjective term!) fail to realize when they meet an American is they are not meeting someone who represents American culture, but only represents one of the cultures in the nation of the United States. Thus, the US appears confusing and contradictory to the rest of the world because we are a contradiction.