We are, on earth, two distinct races. Those who have need of others, whom others amuse, engage soothe, whom solitude harasses, pains, stupefies, like the movement of a terrible glacier or the traversing of the desert; and those, on the contrary, whom others weary, tire, bore, silently torture, whom isolation calms and bathes in the repose of independency, and plunges into the humors of their own thoughts. In fine, there is here a normal, physical phenomenon. Some are constituted to live a life outside of themselves, others, to live a life within themselves. As for me, my exterior associations are abruptly and painfully short-lived, and, as they reach their limits, I experience in my whole body and in my whole intelligence an intolerable uneasiness. 
Guy de Maupassant
humanity, life