People who smile for no reason

You ever meet one of those people who smile for no reason? They'd just be chillin' at their desk, shuffling a bunch of paperwork, and they'd have this big ass smile on their face.

I don't hold it against them, don't get me wrong. It's just that I
actually have to work up to that level of happiness.

I wonder about those folk. What are they smiling about? Are they part
dog? Now, dogs will be happy for the stupidest of reasons. You can
say, "Hey, Spot. Look! Bone," and the dog will start barking with his
tail waving frantically back and forth.

Those people who smile for no reason are like that. I used to work
with an intern named Scott. He'd smile for no reason. I'd be walking
the hallway, pretending to be busy and see Scott at his desk in front
of the computer with a big smile on his face. Was he looking at porn?
Well, I'd walk right up to him to find out and he wouldn't make any
fast movements to close windows. That means, no porn. Nope, he'd be
happy for no reason. Amazing.

He had a girlfriend and she was hot. That's one of the perks of being
happy for no reason. Hot people like you. She smiled for no reason
too. I wonder if they were really aliens sent to observe Earthlings.
They weren't exactly rich either. I know I'd be smiling all the time
if I were rich. And they weren't on Prozac. I've known people on
Prozac and their smiles were different. It was kind of a smile that
as soon as the Prozac wore off, would turn upside down into a big ass
frown. You could always tell a Prozac smile is not really a genuine
smile. I'm talking about a smile for no reason smile.

Anyways, anyone know someone like that, whose default facial expression
is a smile? Ever wonder why?