If you are able to keep quiet in a noiseless place, that kind of quietness does not count for much; only the quietness that is obtained from hard work accords completely with man's nature. If you are able to keep happy on a joyous occasion, that is not happiness in the real sense; only the happiness gained in misery is the source of vitality for man's body and soul.
The genuine tranquility is not that attained amidst quietude but that attained amidst noisy conditions, which counts as the realm of man's natural characters. The real delight is not that sought on joyous occasions but that sough under adverse circumstances, which counts as the true subtlety of man's hearted feelings.
The peace of mind in peaceful surroundings is no real peace of mind; the peace of mind acquired in disturbing circumstances only is the ultimate condition of one's nature. The joy on joyful occasions is no real joy; the joy obtained in sorrowful situations alone is the ultimate delight of one's instinct.