I have a bad case of Resting Bitch Face and I got fired from my barista job at Starbucks for not smiling enough and because I apparently "always looked like I wasn't enjoying myself" while at work.
My "default" settings face just looks serious, sorry, I can't help it.
I was fired from Shopko for the same thing after being promised I was hired as permanent rather than seasonal. Of course, it didn't seem to be a problem until after the holiday rush. Clowns.