[dmarlow]

The brain is an organ. If I could flex my brain, I would!

[manmal]

Of course it is. I think we all know how brains work physiologically (at least basically).

But use it, and it will tire. Forget to pause and it will tire faster. And neurotransmitters are not an endless resource.

[dmarlow]

Just because it's not an endless resouce doesn't mean it's a muscle. Your liver isn't an endless resource.