“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.” 

― Susan Cain, Quiet: The Power of Introverts in a World That Can't Stop Talking