It was said a lot about Russian smile, its absence to be more exact. Maybe you heard the Russian proverb Смех без причины - признак дурачины (a laughter without reason is a sign of insanity).

Russians find American smile insincere, they can’t get used to it and because of that they don’t like it. They regard American smile artificial as Russian put a lot of meaning in their smiles. Satirist Zadornov called the American smile “chronic,” another satirist Zhvanetskiy described it as a person is plugged into an electrical outlet.

Russian don't realize that a smile for Americans is not only a showing of joy, but rather it can be a sign of politeness. It may sound strange for you, but in certain situations you'd better not smile in Russia, as you would be regarded not serious and it's a big flaw!

I, myself, don't like when a person smiles at me when I see he or she doesn't like me or doesn't care about me at all. 

From another side I see nothing wrong in smiling when someone is trying just to be polite. What I really don't like it's to smile when I don't feel like it, I still smile as I am trying to be a polite person but it makes me feel uncomfortable.