Schwartz's research suggests something important: we can stretch our personalities, but only up to a point. Our inborn temperaments influence us, regardless of the lives we lead. A sizeable part of who we are is ordained by our genes, by our brains, by our nervous systems. And yet the elasticity that Schwartz found in some of the high-reactive teens also suggests the converse: we have free will and can use it to shape our personalities.

Solitude is one of our great superpowers... Solitude is the key to being able to make effective decisions and then having the courage of convictions to stand behind those decisions.

I get a lot of letters from introverts asking how they can meet people. The key is to make sure that you are doing things you enjoy.

Jealousy is an ugly emotion, but it tells the truth. You mostly envy those who have what you desire.

Though shyness per se was unacceptable, reserve was a mark of good breeding.

I'm insatiably curious about human nature.

But when the group is literally capable of changing our perceptions, and when to stand alone is to activate primitive, powerful, and unconscious feelings of rejection, then the health of these institutions seems far more vulnerable than we think.