Shyness is the fear of social disapproval or humiliation, while introversion is a preference for environments that are not overstimulating. Shyness is inherently painful; introversion is not.

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

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.

Or at school you might have been prodded to come “out of your shell”—that noxious expression which fails to appreciate that some animals naturally carry shelter everywhere they go, and that some humans are just the same.

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

Whoever you are, bear in mind that appearance is not reality. Some people act like extroverts, but the effort costs them energy, authenticity, and even physical health. Others seem aloof or self-contained, but their inner landscapes are rich and full of drama. So the next time you see a person with a composed face and a soft voice, remember that inside her mind she might be solving an equation, composing a sonnet, designing a hat. She might, that is, be deploying the powers of quiet.

Now that you're an adult, you might still feel a pang of guilt when you decline a dinner invitation in favor of a good book. Or maybe you like to eat alone in restaurants and could do without the pitying looks from fellow diners. Or you're told that you're "in your head too much", a phrase that's often deployed against the quiet and cerebral. Or maybe there's another word for such people: thinkers.