Hence the saying: If you know the enemy and you know yourself, your victory will not stand in doubt; if you now Heaven and you know Earth, you may make your victory complete. ↗
When life was worrying about a car payment or a rent payment and a bill, you're so consumed with that, you really don't have time to know yourself. That's surviving and getting by. ↗
Only as you do know yourself can your brain serve you as a sharp and efficient tool. Know your own failings, passions, and prejudices so you can separate them from what you see. ↗