"Even though we can reach for the outer limits of our temperaments, it can often be better to situate ourselves squarely inside our comfort zones. . . . Once you understand introversion and extroversion as preferences for certain levels of stimulation, you can begin consciously trying to situate yourself in environments favorable to your own personality--neither overstimulating nor understimulating, neither boring nor anxiety-making. You can organize your life in terms of what personality psychologists call "optimal levels of arousal" and what I call "sweet spots," and by doing so feel more energetic and alive than before."