My problem is that I don't have a resting/neutral face. 

If I'm not thinking about my face, it's a freeze-frame of a chaotic configuration of clenched and unclenched muscles. Like if I had to squint an eye because someone's watch reflected a sunbeam into my face, there's a good chance I'll be slightly squinting 15 min later.

But that's the best case scenario -- that I'm simply unaware of my face.

The losing battle comes when I become self-aware of my face. 

I'll be walking to work and I'll suddenly recall a Tony Robbins quote about how you should always wear a slight smile. You know, brighten up my day and everyone's that sees me just like Tony says. So I'll try to apply that morsel of advice to my own face. Clenching the right muscles to approximate someone that smiles naturally as they walk down the street. Clench and hold. 10 min later I do a clench-check. Am I still smiling? Too small of a smile? Too large? I realize that I'm actually frowning now and my left eye is squinting again, muscle memory from the watch reflection 5 hours ago.