I'd read this, and spent a couple weeks in Russia last fall, and noticed the lack of smiling a lot when I was there. The thing that struck me about that mindset, and particularly that phrase (and others like it) is that it presumes the person looking at me knows if I have a reason to smile/laugh or not.

There's no doubt a lot of layers in the thinking that produced that (and similar) phrases which I can't unravel or fathom, but it's still strange all the same. To presume someone is stupid if you see them laughing is certain a cultural thing. Here (US) we'd probably just assume they were happy.

But on the flip side, a lot of people in the U.S. would assume someone is sad or angry if they are not smiling. There are examples in comments here.

>> Russians need a particular reason to smile. You've heard good news and you smile to show that you consider this news as good.