Confidence/mental side is so important. I have a good friend who had all the ability and none of the confidence. Through high school he should have resorted to, "Here it comes. Try and hit it." But he feared failure. It ate him up. He was a mediocre player from LL through high school/Legion. His one stellar year was his post senior year of Legion. This one season convinced the D1 coach of a successful program to invite him to walk on.
Being good friends I talked to him about his problems along the way. He was afraid if the first pitch to a hitter was a ball he was on his way to 2-0 and having to groove a pitch. How often do you think this became a self fulfilling prophecy. As rival friends he wanted to get me out so badly he either hit me or grooved a pitch.
In my first year of college summer ball I played with a couple of guys from his college program. When my friend took the mound one said, "Look, BP is pitching!" It was the nickname he acquired in college grooving pitches in scrimmages. He was released after the fall of soph year.
Even as a mature adult he's still an Eeyore. He was pissing an moaning about how the Patriots were going to lose to the Texans during the first half (winning 14-13). Then he asked how I could stay so calm. I told him it's the coach in me. I couldn't overreact when I coached. I didn't overreact when I played either. The Patriots are playing as badly as they can possibly play and they're winning. They're prepared. They're better. They will be fine. Final 34-16.