IT IS THE CONSTANT “THINKING” activity of Self 1, the ego-mind, which causes interference with the natural capabilities of Self 2. Harmony between the two selves exists when this mind is quiet and focused.

When a tennis player is “in the zone,” he’s not thinking about how, when or even where to hit the ball. He’s not trying to hit the ball, and after the shot he doesn’t think about how badly or how well he made contact. The ball seems to get hit through a process which doesn’t require thought. There may be an awareness of the sight, sound and feel of the ball, and even of the tactical situation, but the player just seems to know without thinking what to do.

From "Zen in the Art of Archery":
As soon as we reflect, deliberate, and conceptualize, the original unconsciousness is lost and a thought interferes. … The arrow is off the string but does not fly straight to the target, nor does the target stand where it is. Calculation, which is miscalculation, sets in….
Man is a thinking reed but his great works are done when he is not calculating and thinking. “Childlikeness” has to be restored…

Perhaps this is why it is said that great poetry is born in silence. Great music and art are said to arise from the quiet depths of the unconscious, and true expressions of love are said to come from a source which lies beneath words and thoughts. So it is with the greatest efforts in sports; they come when the mind is as still as a glass lake.

Maslow, in such "peak experiences" use those phrases:
“He feels more integrated” [the two selves are one], “feels at one with the experience,” “is relatively egoless” [quiet mind], “feels at the peak of his powers,” “fully functioning,” “is in the groove,” “effortless,” “free of blocks, inhibitions, cautions, fears, doubts, controls, reservations, self-criticisms, brakes,” “he is spontaneous and more creative,” “is most here-now,” “is non-striving, non-needing, non-wishing … he just is.”

During such experiences, the mind does not act like a separate entity telling you what you should do or criticizing how you do it. It is quiet; you are “together,” and the action flows as free as a river.

The image comes to my mind of the balanced movement of a cat stalking a bird. Effortlessly alert, he crouches, gathering his relaxed muscles for the spring. Not thinking about when to jump, nor how he will push off with his hind legs to attain the proper distance, his mind is still and perfectly concentrated on his prey. No thought flashes into his consciousness of the possibility or consequences of missing his mark. He sees only bird. Suddenly the bird takes off; at the same instant, the cat leaps. With perfect anticipation he intercepts his dinner two feet off the ground. Perfectly, thoughtlessly executed action, and afterward, no self-congratulations, just the reward inherent in his action: the bird in the mouth.

Quieting the mind means less thinking, calculating, judging, worrying, fearing, hoping, trying, regretting, controlling, jittering or distracting.
The mind is still when it is totally here and now in perfect oneness with the action and the actor.

These inner skills are really arts of forgetting mental habits acquired since we were children.
The first skill to learn is the art of letting go the human inclination to judge ourselves and our performance as either good or bad.
When we unlearn how to be judgmental, it is possible to achieve spontaneous, focused play.

LETTING GO OF JUDGMENTS

"goodness" or "badness" are evaluations added to the event in the minds of the players according to their individual reactions.

it is the initial act of judgment which provokes a thinking process.
If he judges it as bad, he begins thinking about what was wrong with it. Then he tells himself how to correct it.
If the shot is evaluated as good, Self 1 starts wondering how he hit such a good shot; then it tries to get his body to repeat the process by giving self-instructions, trying hard and so on. Both mental processes end in further evaluation, which perpetuates the process of thinking and self-conscious performance. As a consequence, the player’s muscles tighten when they need to be loose, strokes become awkward and less fluid, and negative evaluations are likely to continue with growing intensity.

After Self 1 has evaluated several shots, it is likely to start generalizing. Instead of judging a single event as “another bad backhand,” it starts thinking, “You have a terrible backhand.” Instead of saying, “You were nervous on that point,” it generalizes, “You’re the worst choke artist in the club.” Other common judgmental generalizations are, “I’m having a bad day,” “I always miss the easy ones,” “I’m slow,” etc.

It is interesting to see how the judgmental mind extends itself. It may begin by complaining, “What a lousy serve,” then extend to, “I’m serving badly today.” After a few more “bad” serves, the judgment may become further extended to “I have a terrible serve.” Then, “I’m a lousy tennis player,” and finally, “I’m no good.” First the mind judges the event, then groups events, then identifies with the combined event and finally judges itself.

As a result, what usually happens is that these self-judgments become self-fulfilling prophecies. That is, they are communications from Self 1 about Self 2 which, after being repeated often enough, become rigidified.

If the judgment process could be stopped with the naming of the event as bad, and there were no further ego reactions, then the interference would be minimal. But judgmental labels usually lead to emotional reactions and then to tightness, trying too hard, self-condemnation, etc.
This process can be slowed by using descriptive but nonjudgmental words to describe the events you see.

When we plant a rose seed, We stand in wonder at the process taking place and give the plant the care it needs at each stage of its development. The rose is a rose from the time it is a seed to the time it dies. Within it, at all times, it contains its whole potential. It seems to be constantly in the process of change; yet at each state, at each moment, it is perfectly all right as it is.

Similarly, the errors we make can be seen as an important part of the developing process.
our tennis game gains a great deal from errors.

The first step is to see your strokes as they are. They must be perceived clearly. This can be done only when personal judgment is absent. As soon as a stroke is seen clearly and accepted as it is, a natural and speedy process of change begins.

DISCOVERING NATURAL LEARNING

We walked over to a large windowpane and there I asked him to swing again while watching his reflection.
he was astounded. “Hey, I really do take my racket back high! It goes up above my shoulder!” There was no judgment in his voice; he was just reporting with amazement what his eyes had seen.
What surprised me was Jack’s surprise. Hadn’t he said that five pros had told him his racket was too high? I was certain that if I had told him the same thing after his first swing, he would have replied, “Yes, I know.” But what was now clear was that he didn’t really know.

Jack was able to keep his racket low quite effortlessly as he swung again. “That feels entirely different than any backhand I’ve ever swung,” he declared. By now he was swinging up and through the ball over and over again. Interestingly, he wasn’t congratulating himself for doing it right; he was simply absorbed in how different it felt.

“I can’t tell you how much I appreciate what you’ve done for me. I’ve learned more in ten minutes from you than in twenty hours of lessons I’ve taken on my backhand.”
“I can’t remember your telling me anything! You were just there watching, and you got me watching myself closer than I ever had before. Instead of seeing what was wrong with my backhand, I just started observing, and improvement seemed to happen on its own. I’m not sure why, but I certainly learned a lot in a short period of time.”
He had learned, but had he been “taught”? This question fascinated me.

The key that unlocked Jack’s new backhand—which was really there all the time just waiting to be let out—was that in the instant he stopped trying to change his backhand, he saw it as it was. At first, with the aid of the mirror, he directly experienced his backswing. Without thinking or analyzing, he increased his awareness of that part of his swing. When the mind is free of any thought or judgment, it is still and acts like a mirror. Then and only then can we know things as they are.

AWARENESS OF WHAT IS

In the game of tennis there are two important things to know. The first is where the ball is. The second is where the racket head is.
you simply watch the ball and let the proper response take place.
In the same way, you don’t have to think about where your racket head should be, but you should realize the importance of being aware of where the racket head is at all times. You can’t look at it to know where it is because you’re watching the ball. You must feel it.
Feeling it gives you the knowledge of where it is. Knowing where it should be isn’t feeling where it is. Knowing what your racket didn’t do isn’t feeling where it is. Feeling where it is is knowing where it is.

No matter what a person’s complaint when he has a lesson with me, I have found that the most beneficial first step is to encourage him to see and feel what he is doing—that is, to increase his awareness of what actually is.
the player may ask where his racket should be when the ball is bouncing. But I decline to say, asking him only to observe where his racket is at that moment.

After he hits a few balls, I ask him to tell me where his racket was at the moment in question. The typical reply is, “I’m taking my racket back too late. I know what I’m doing wrong, but I can’t stop it.” This is a common response of players of all sports, and is the cause of a great deal of frustration.
“Forget about right and wrong for now,” I suggest. “Just observe your racket at the moment of bounce.” After five or ten more balls are hit to him, the player is likely to reply, “I’m doing better; I’m getting it back earlier.”

I again ask him to observe his racket and to tell me exactly where it is at the moment of bounce. As the player finally lets himself observe his racket with detachment and interest, he can feel what it is actually doing and his awareness increases. Then, without any effort to correct, he will discover that his swing has begun to develop a natural rhythm. In fact, he will find the best rhythm for himself, which may be slightly different from what might be dictated by some universal standard called “correct.” Then when he goes out to play, he has no magic phrase that must be repeated, and can focus without thinking.

To discover this natural learning process, it is necessary to let go of the old process of correcting faults; that is, it is necessary to let go of judgment and see what happens.

WHAT ABOUT POSITIVE THINKING?

One of the first lessons I learned as a teaching pro was not to find fault with any pupil or even his strokes. So I stopped criticizing either. Instead, I would compliment the pupil when I could, and make only positive suggestions about how to correct his strokes.
Some time later, I found myself no longer complimenting my students.

Always looking for approval and wanting to avoid disapproval, this subtle ego-mind sees a compliment as a potential criticism. It reasons, “If the pro is pleased with one kind of performance, he will be displeased by the opposite. If he likes me for doing well, he will dislike me for not doing well.”

It is impossible to judge one event as positive without seeing other events as not positive.
You can notice exactly how far out a ball lands without labeling it a “bad” event. By ending judgment, you do not avoid seeing what is. Ending judgment means you neither add nor subtract from the facts before your eyes. Things appear as they are—undistorted. In this way, the mind becomes more calm.

“if I see my ball going out and I don’t evaluate it as bad, I won’t have any incentive to change it. If I don’t dislike what I’m doing wrong, how am I going to change it?” Self 1, the ego-mind, wants to take responsibility for making things “better.”

The driver is seeing the same girl that the others are observing, but is simply watching what is before his eyes. He sees neither good nor bad, and as a result, a detail comes to his attention which was not noticed by either of his companions: the girl’s eyes are shut.