That is not true. In western countries one must smile to be polite, even if the smile doesn't represent his/her current mood. There is no objective reason to render happines in common situation for Russian people.
One may smile when he meets a friend or sees some cute kitten, but in general people are walking in some meditation alike state, thinking about the current affairs and not particularly paying attention to the people they passing by.
And when russian person meets the grinning stranger with cold eyes (not his real mood). It looks kind of creepy. Ordinary people usually do not pay much attention for this kind of encounters. Police (are you drunk?) and street scammers(are you a tourist?) - do.
That's right, but only few people speak pure Ukranian language (and they do it mainly for political reasons). It is incovinient as it lacks some modern words and concepts. One can discuss prices on the market or neighbor girl, but when topic is switched to scientific or ingeneering matter - Russian is language of choise. Same with Kazakh language - the language of nomads.