Did not quite expect this question to be here. But, as a <i>former</i> Russian, here is my 2 kopeks.<p>One of the reasons I left the country was the clash of cultural codes. I am used to smiling at people for no reason at all, which is normal where I live now (the US, at least the coastal regions). In Russia, this often makes people uncomfortable, and that in turn made me feel awkward. There is a Russian expression, "a laugh without a reason is a sign of insanity" (loose translation), which I could never internalize.<p>Whether there are deeper reasons for this, or just "it so happened" over the centuries, I am not certain.