People who seem unable to smile when you're happy about something, and who seem to smile easily when you're quiet or not really in an overly positive mood.

Discuss.

Don't see the relevance. Some people are just happier than others.

I don't really smile at all, unless something's funnly. I think that's what you mean...

I smile when something goes wrong, lol.

Not literally smile. I mean able to be pleasant or not able to be pleasant.