Amazing! I think people go through a lot they keep hidden. That's why I frown at women who get offended when asked to smile. I get it that you owe no one your smile or attitude for that matter.
But smiling isn't an expression that should be huddled.
Although too much smiling can be creepy for comfort, when you meet someone's gaze or see someone in a bad mood, just smiling at them can tune up their day.
I guess what I'm saying is good or bad smiling should be based on the situation.