https://www.chicagomaroon.com/2002/04/12/why-russians-do-not-smile/, posted 29 May by peter in culture people russia usa
Western people perceive the smile as a sign of a positive approach while Russians necessarily identify the smile with laughter. Western people perceive a smiling person as "happy" and "well-off" person. For Russians happiness and prosperity are not associated with the smile, at least not to the extent they are in the United States. A happy person is not obligated to smile. On the other hand, the smiling man is not necessarily happy or more prosperous than anyone else. Sometimes these states coincide, sometimes not.