[Introverts,] the world needs you and it needs the things you carry. So I wish you the best of all possible journeys and the courage to speak softly.

Love is essential; gregariousness is optional. Cherish your nearest and dearest. Work with colleagues you like and respect. Scan new acquaintances for those who might fall into the former categories or whose company you enjoy for its own sake. And don't worry about socializing with everyone else. Relationships make everyone happier, introverts included, but think quality over quantity.

we have two ears and one mouth and we should use them proportionally

I've never given a speech without being terrified first.

I think the shyness one feels in childhood is often overcome with time. There are children who hide behind their parents' legs, but you don't see grown-ups hiding behind people. It just doesn't happen. I mean, not that often. People develop social skills over time.

In the first study, Grant and his colleagues analyzed data from one of the five biggest pizza chains in the United States. They discovered that the weekly profits of the stores managed by extroverts were 16 percent higher than the profits of those led by introverts—but only when the employees were passive types who tended to do their job without exercising initiative. Introverted leaders had the exact opposite results. When they worked with employees who actively tried to improve work procedures, their stores outperformed those led by extroverts by more than 14 percent.

America had shifted from what influential cultural historian Warren Susman called a culture of character to a culture of personality, and opened up a Pandora's box of personal anxieties of which we would never recover.