If you know the enemy and you know yourself, you need not fear the result of a hundred battles. If you know yourself but not the enemy, for every victory gained you will also suffer a defeat. If you know neither the enemy nor yourself, you will succumb in

You will become way less concerned with what other people think of you when you realize how seldom they do

I will not pass judgment on what is exciting and honorable

Weird doors open. People fall into things.