We’ve evolved to be smart enough to make ourselves sick.

We live well enough to have the luxury to get ourselves sick with purely social, psychological stress.

We all seek out stress. We hate the wrong kinds of stress but when it's the right kind, we love it - we pay good money to be stressed by a scary movie, a roller coaster ride, a challenging puzzle.

The regulation of genes is often more interesting than the genes themselves, and it's the environment that regulates genes.

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.

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

Almost always, genes are about potentials and vulnerabilities rather than about determinism.