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.

What looks like multitasking is really switching back and forth between multiple tasks, which reduces productivity and increases mistakes by up to 50 percent.

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.

Evangelicalism has taken the Extrovert Ideal to its logical extreme...If you don't love Jesus out loud, then it must not be real love. It's not enough to forge your own spiritual connection to the divine; it must be displayed publicly.

Persistence isn't very glamorous. If genius is one percent inspiration and ninety-nine percent perspiration, then as a culture we tend to lionize the one percent. We love its flash and dazzle. But great power lies in the other ninety-nine percent.

[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.

(Finland is a famously introverted nation. Finnish joke: How can you tell if a Finn likes you? He's staring at your shoes instead of his own.)