The terrifying fear of a crash had triggered the fight-or-flight response in the child, making him burn a mule, but only he knew about it—thanks to his tight and reliable underpants.

He tried to decide if he was really ashamed of being afraid, and decided that he was not. Fear was there for a purpose. It was wired into any creature that had not completely turned its back on its evolutionary inheritance and so remade itself in whatever image it coveted. The more sophisticated you became, the less you relied on fear and pain to keep you alive; you could afford to ignore them because you had other means of coping with the consequences if things went badly.

The detection of a person as safe or dangerous triggers neurobiologically determined pro-social or defensive behaviors.
Even though we may not always be aware of danger on a cognitive level, on a neurophysiological level, our body has already started a sequence of neural processes that would facilitate adaptive defense behaviors such as fight, flight or freeze. 

When you become aggressive in arguments, you force the other person to become defensive which means they’ll either get ready to fight you or ready to flee from you.

I also know about running away," I said, "when staying around is so much harder. And I know the happiness, the"-I searched for a word and had to settle on- "the joy when sticking around and fighting things mean I get to keep the people I love near me.

I also know about running away," I said, when staying around is so much harder. And I know the happiness, the"-I searched for a word and had to settle on- "the joy when sticking around and fighting things mean I get to keep the people I love near me.