" A person or team which is not humble cannot get better. This is because they think they already have everything mastered. They think they already have done enough to succeed. They think they already know all of the answers.  Once someone has had some success, be it large or small, they frequently get satisfied, even a little lazy. They think the way they worked yesterday was good enough, so they struggle to work hard today. As a result, they stay still as the humble advance. "

― , On Character and Mental Toughness