I think the reason some people do it is that they somehow think they're really making you happier. They say "smile" and if you do they must have somehow fixed your problems. (??) Part of me is thinking "this person must be sort of delusional." But maybe it's kind of a power play. I mean any time a complete stranger is like, "do this thing for me..." it's just weird. I always wanna be like, "no, you smile dude."

Anyway... Rohag has a good point. You don't have to smile in Russia. I kind of like that. Some people (Americans) say everyone looks depressed. I think it's freeing. You don't have to put on an act. You can be honest about how you feel and don't have to fake it.