Jaw-Clencher
I know I do it when I’m working in the studio, concentrating and focused.
I’m trying to be mindful and catch myself doing it so I can purposefully relax my jaw.  I’m shocked at how often I catch myself.  I think I spend over 50% of my day in clench-mode.  Strangely, too, I’ll often be aware I’m doing it as I wake up.  
Which means I must be doing it in my sleep.
Which means I’m probably doing it more like 80% of my day.
That can’t be good.