In my not-so-humble opinion, this goes way further than schizoaffective disorder -- it's a symptom of a culture that puts inordinate emphasis on simulating happiness:

(1) Take a look at advertising. Think of any time you saw a woman (key word alert) depicted as ecstatic over a floor cleaner, cell phone, lipstick color, etc. To further this effect, some are shown with more garish makeup than the average circus clown.

(2) I've never understood why no one can be photographed (except on driver licenses and police mug shots) without being commanded to smile. I once tried to look serious and dignified in a family portrait session and was fooled into laughing by the photographer; I looked like a giggly jackass afterward, but mom and dad loved that "just right expression" (actual phrase used in Olan Mills pamphlets for parents).

(3) Mom's way of dealing with any negative emotions was to pretend she didn't feel them -- and she expected the same of me. I have no doubt this has driven much of my depression; whether or not she meant well makes no difference.

(4) Complete strangers have sneered, "C'monnnnn, give us a smile" at my wife for no other reason than that she's a woman.

[/depressive rant]