Do you know, why? Many foreigners have come to Russia while Petr The First was a tsar. There were Germans, Dutch, Swedes, Danish people, etc. The majority of Russians didn't speak their languages and called them 'mute' because 'they don't speak our language so they're mute'. Then this demonym was assigned to Germans, other nations was named according to names of their countries. :).
"Mute", because they didn't speak a Slavic language. There's a theory that Slavs/Slavic (I mean word for Slavic and Slavs in Slavic languages) means something like "speaking (lit. using words)", because long time ago there was one Proto Slavic language used by Slavs and a dozen of other they couldn't understand.
So people don't smile here... Out of curiosity, how much do people smile "unprovoked" in Ukraine and Russia? I've heard that a smile without a reason is a sign of a weak mind, but there are people in about every country that say similar things. So are smiles generally common, or saved for special occasions?