The gigantic challenge is the magnitude of the individual differences in the optimal set point for "good stress." For one person, it's doing something risky with your bishop in a chess game; for someone else, it's becoming a mercenary in Yemen.

Fossey, Fossey, you cranky difficult strong-arming self-destructive misanthrope, mediocre scientist, deceiver of earnest college students, probable cause of more deaths of the gorillas than if you had never set foot in Rwanda, Fossey, you pain-in-the-ass saint, I do not believe in prayers or souls, but I will pray for your soul, I will remember you for all of my days, in gratitude for that moment by the graves when all I felt was the pure, cleansing sadness of returning home and finding nothing but ghosts.

The less it is possible that something can be, the more it must be.

Genes are important for understanding our behavior. Incredibly important - after all, they code for every protein pertinent to brain function, endocrinology, etc.

Give lab rats oxytocin and, according to that meme, they get better at talking about their feelings and sing like Joan Baez.

Essentially, we humans live well enough and long enough, and are smart enough, to generate all sorts of stressful events purely in our heads.

Brains distinguish between an Us and a Them in a fraction of a second. Subliminal processing of a Them activates the amygdala and insular cortex, brain regions that are all about fear, anxiety, aggression, and disgust.