system
Given the following post, respond as if you're commenting on Reddit:
human
Why do most of us stick out our tongues in some fashion when we're concentrated on doing something?

Edit: Yes, I do mean most of us. 

It's also interesting to note that we all have different variations of sticking out our tongue. Some of us move them around, while others chew on them or simply stick them out. Additionally, I found that some things I would expect to trigger this for me don't, while others do. I am completely straight faced when I play guitar, but when I start coloring, I look like a little kid again.
gpt
Sticking your tongue out or biting your lip while concentrating is not really that weird.  Michael Jordan was famous for his tongue sticking out while going up for a dunk. It is an example of what’s called motor overflow or motor disinhibition. It happens sometimes when our brains are working really hard at something.  Normally, the brain keeps the brakes on the parts of the body it doesn’t want to move. However, when we concentrate really hard on a tough task, sometimes the brain lifts the brakes on other parts of the body (most often the face, lips, tongue, etc.) making them move without our control. As we get older our brains get better at controlling the brakes (inhibition) and the motor overflow goes away most of the time, but some people still have this happen when they are grown ups. There are studies that show it is more common in people with ADHD.