Great stuff from sports psychologist Gary Mack's book "Mind Gym" about a conversation he once had with Edgar Martinez, a 7-time MLB All-Star who spent all 18 years of his pro career with the Seattle Mariners.
At one point during their conversation, Mack asked Martinez to describe what he worked on as he moved from the minors to the majors. Surprisingly, it had nothing to do with batting or fielding.
"I worked a lot on my emotions," said Martinez. "I don't have a real bad temper, but I can remember some things I've done in the past, like hit the wall or hit the helmet box. But I learned from experienced players that that's not the way you do it. Don't let your teammates or the other team know that you're down or struggling. It's going to hurt your teammates because they're not going to trust you. If you're going to get upset, don't do it on the field. Go into the bathroom, or someplace where you are along and just let it go."As Mack writes, "the best athletes [and coaches] are masters of their emotions and not servants to them."