Sims smile too much
The constant smile and happiness is odd. I don't think sims feel REAL happiness if they are "happy" all of the time. I think fine should be the default emotion, it is more realistic.
Forum Discussion
I find it helpful to stick the Genius trait on any sims who I absolutely don't want to go around grinning all the time. They can still smile and be happy, but most of them don't do it all the time if they're a genius (real or fake, lol). Edited to add: It's because they very often become focused, which overrides most of the happy-happy look.
