When I was committed to a psych ward, one of the nurses repeatedly told me to smile if I wanted any chance of getting out. (My doctor is still amazed they kept me. It was a mess, and it wasn't where I needed to be.)
I thought. . ."Really? The mental health community is asking me to fake emotions to *get out*? One of many reasons I have such bad memories of a place that took me backwards, not forwards.
Unrelated, sometimes I think people say *smile* out of selfishness. It is uncomfortable for them to bare witness to another person's pain. My guess is they have no idea that their statements are self-motivated.