Some people are so used to solitude with themselves that they never compare themselves to others, but spin forth their monologue of a life in a calm, joyous mood, holding good conversations with themselves, even laughing. But if they are made to compare themselves with others, they tend to a brooding underestimation of their selves; so that they have to be forced to learn again from others to have a good, fair opinion of themselves. And even from their learned opinion they will always want to detract or reduce something.
Thus one must grant certain men their solitude, and not be silly enough, as often happens, to pity them for it.
From 'Man Alone with Himself' by Friedrich Nietzsche.