“If I told people they could win a major [golf] championship by spending an hour a night walking across a bed of hot coals, many of them would immediately start taking off their shoes and socks. But the thought of spending that same hour working on their psyche doesn’t appeal to them. Maybe it’s because a physical or mechanical flaw seems to be a little farther from the core of a person’s identity. A thinking flaw strikes closer to who we are.”