Americans aren't socially unmoored. We come from a society where people smile as a matter of being polite. People everywhere have to learn social signals and ours happen to involve smiling as a matter of course.

This thread is pretty irritating for being kind of clueless to the reality that every culture on earth is going to have trappings like this and the alleged stoicism of Russia and Germany are no exception. (Thinking someone is simple or mentally ill because they smile too much is already such a trapping.)