When you start out you have to think about a million different things. "Never keep more than 100 things in your mind during a golf swing" Dr. Parent advices in "Zen Golf", but it sure feels like that would be quite a trick. "Left arm straight", "Keep your eyes on the ball", and "Don't move your head" are just a few. And you practice and practice, and you get a little better.
Then you eventually get to the point where you have these things pretty much down pat. Now you have to start worrying about things like body turn and tempo. Maybe someting about your swing plane or your finishing position. And you practice and practice, and you get a little better still.
Now you get into the rarified air where your swing thoughts no longer have anything to do with the physical aspects of your golf swing. I've played golf for 35 years, and I've only been there once. On the range last fall I found myself with only one thought: Visualizing, in super-slow-motion, the face of the club making contact with the ball. I hit Driver and irons, and I was making beautiful contact with the ball. The shots were effortless and straight, and I was smiling from ear to ear.
It was then that I realized that if I were to tell a beginning golfer to have the same image in their head would be an absolute disaster. They'd be lucky to make contact at all without focusing on all that other crap.
It was a lot of fun being in that place, and I'm working hard to be able to get back there.
And, maybe just maybe, I will one day be able to just "Be the ball".