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.
And yes, if you smile too much you are taken for лох, even if you are native. Get to an urban market some day and smile to sellers, посчитай на сколько обуют.
>>The virile ruler, the vodka, the endless mounds of sour cream—they are pleasing to some. It’s just that grinning without cause is not a skill Russians possess or feel compelled to cultivate. There’s even a Russian proverb that translates, roughly, to “laughing for no reason is a sign of stupidity"
Your average street level transaction will degrade if you smile or even too polite.