You have three brains; your ancient Chimp brain (keeps you alive), your modern Professor brain (navigates the civilized world), and your Computer brain (accesses memories and runs your habits, both good and bad. They fight for control all the time; you get crazy nervous before a race, you choke under pressure, you quit when the going gets tough, you make dumb mistakes, you worry about how you look. Feeling unworthy of being called an athlete (runner, triathlete, cyclist) is referred to as cognitive distortion, but can also work both ways. Being overconfident can be as damaging as being under confident. How does each happen? 

Drawing from the book "The Brave Athlete" by Dr. Simon Marshall and Lesley Paterson (https://www.velopress.com/books/the-brave-athlete/), a book recently recommended to John by Beth Shaw after reading of his ongoing anxiety about the open water swim, the guys talk about these and some of the points made in the book. 

Well, at least the first 1/3 of the book.