And its inverse: "Don't confuse your account balance with intelligence." (Very important during a bull market, when everyone is a genius.)
"Amateur looks to make money, a professional concerns himself with doing the right thing, knowing that profit takes care of itself if other things are attended to." -Jesse Lauriston Livermore
Fear, that's the other guys problem! https://getyarn.io/yarn-clip/34bd4f17-5834-4212-b9a2-6d8c03745057