The most intelligent men, like the strongest, find their happiness where others would find only disaster: in the labyrinth, in being hard with themselves and with others, in effort; their delight is in self-mastery; in them asceticism becomes second nature, a necessity, an instinct. They regard a difficult task as a privilege; it is to them a recreation to play with burdens that would crush all others.
Friedrich Nietzsche, from The Antichrist (Der Antichrist), §57, H. L. Mencken translation.