Just the ball is moving
I was tempted to drop this post into the 'Wisdom of Jeff Van Gundy' series, but since JVG didn't actually relate the following observation I am going to drop, let's just call this the (unofficial) start of a new series titled 'The Wisdom of Martina Navratilova'.
Tennis legend Martina was doing the TV commentary of a recent French Open match I was half-watching when one of the players missed an easy volley at the net. The slow-motion replay showed he had (slightly) looked up from the ball coming to his racket, and seemed to look over the net to the spot where he was aiming the shot.
Here's what Martina said (more or less), after the missed shot and replay:
He looked where he was going to hit the ball, and that is such a common mistake for regular players, club players, and even the professionals. Of course you want to see where you are going to hit the ball, but the problem is you stop seeing the ball. The court is not moving, just the ball is moving. You have to watch the ball, and that is such an easy mistake to make.
Fantastic observation from Martina, (who was always my choice before Evert by the way), about not only the importance of concentration, but the need to focus on what really matters, and to let go of the things that are not fundamental or important to what you are trying to accomplish.
It's kind of a different spin on the old classic advice to focus on the things you can control and not on the ones you can't. In tennis, you need to focus on the very thing you can't control, i.e. the ball, and not spend time on the other thing you also can't control, the court, but the one you can't impact.
You may not always get the outcome you like, but you can at least try and influence the ball, so you'd better concentrate on that.
The same idea is likely applicable in many other contexts as well. It makes no sense to fixate on the things that we not only can't control, but we have no ability to change.