There’s a lot of interesting and valuable material in this thread. I’m going to make a couple of observations, some of which will echo what others have said. I’m afraid that I haven’t noted my predecessors in the thread where that qualification applies. Keep in mind that I myself am the “test.” That is, if you can’t beat me in pool you can’t play pool.
#1. Recall for a second Steve Cook. I have in my mind a quote from Cook when he was asked how much he practiced. He is supposed to have said that he could not practice the way his competition did. He claimed he had two strokes. He had a stroke he fell into when he practiced and a stroke he fell into naturally when he played in competition. He claimed it was pointless for him to practice because he knew that as soon he was in competition his practice stroke would disappear and his competitive stroke would take over. No, I don’t have a source.
In the same way, I recently heard a snooker player talk about an opponent of his who missed a very simple shot at a critical moment. The speaker said that later he passed a practice table and his former opponent was practicing the same simple shot over and over. The speaker reflected that there was no doubt at all in his own mind that his opponent could make the ball fifty times in a row practicing. The question was why he had missed such a simple shot one time in competition. That was what the opponent should be investigating — in the terms of Steve Cook, what was wrong with his competitive stroke.
#2. A music pedagogue named Eloise Ristad some years ago published a book about musical performance titled “A Soprano on Her Head.” If you are interested in overcoming choking you might want to look it up. (In music conservatories they don’t use words like “choking” or “dogging it.“ The professional expression is “performance anxiety.”) She addresses extremely long sessions of practice. Like Calvin Coolidge’s minister on the subject of sin, she’s “agin it.” She thinks if you are putting in long, long sessions of practise, then you are practicing wrong. Someone in the thread above said, “Perfect practice makes perfect.” Bob Byrne’s expression was, “Practice does NOT make perfect. It makes PERMANENT.” You can be digging yourself a hole If you’re doing it wrong.
In addition Ristad draws attention to the physical damage long hours of practice can cause.