"You may not smile in Arkansas, Indiana, Nevada, or Virginia." At least, not if you are getting your driver's license photo taken.
Apparently, they use photo detection software to compare faces for identity fraud purposes. And smiling thwarts the computer.
Is it even legal (or constitutional) to require drivers to not smile? Can they frown? Stick out their tongues? Look cross-eyed? (Interesting face research where you can combine 2 faces; and a blog on pics of faces in places; and make your own Flash face like Mr Potato Head).
I supposed DMV would prefer folks who are depressed when they get their photo taken, to keep the computers happy. One man's downer is another machine's Prozac.