Doing Nothing to Enhance Creativity, article. Another one from S. Shapiro.
I've noticed this in myself to a high degree in recent years. I have a hyper-active mind which I find nigh impossible to quiet down, sometimes irritatingly. One of the exceptions is when I am really, really relaxing, in the dark or at least darkened room, on or in my bed.
And not the least of it happens, as the article talks about, when I am halfway between awake and asleep. I've had many amazing mental experiences and developments in this state.
Action is counter-productive to deep thought, and deep thought is counter-productive to action. I think it's a good thing to make time, separate times, for both in life.
Update: here's another vote for relaxing, it seems that an afternoon nap markedly boosts the brain's learning capacity.