To this end we must not only consider those aspects of life which have been denied hitherto, as: necessary, but as desirable, and not only desirable to those aspects which have been affirmed hitherto (as complements or first prerequisites, so to speak), but for their own sake, as the more powerful, more terrible, and more veritable aspects of life, in which the latter's will expresses itself most clearly.
— from The Will to Power: An Attempted Transvaluation of All Values. Book III and IV by Friedrich Wilhelm Nietzsche