duuuuh...

All my life, from childhood to now, I've been taught to keep my mouth closed. I would mentally make fun of people who walked around with their mouth open. I even played a character in college who always had his jaw dropped because the guy was supposed to be a little 'slow.'

As it turns out, holding your jaw all the time creates tension that radiates to other parts of your body. Especially when you're performing a phsyical activity such as sports, exercise, household chores, or acting, it will only benefit you to loosen your jaw and let your lips part, even just a little bit. You even listen better with your jaw hanging.

It's why Michael Jordan always had his tongue out when he made a spectacular dunk. It's one of the things that made Muhammad Ali great- go back and watch the video. (Although it did contribute to his getting his jaw broken by an opponent once.)

Next time you see somebody on the bus or in a movie theater with his jaw hanging slack- don't hate. He may just be a trained actor.