Nietzsche: a human being should attain satisfaction with himself

For one thing is needful: that a human being should attain satisfaction with himself, whether it be by means of this or that poetry and art; only then is a human being at all tolerable to behold. Whoever is dissatisfied with himself is continually ready for revenge, and we others will be his victims, if only by having to endure his ugly sight. For the sight of what is ugly makes one bad and gloomy.

• Friedrich Wilhelm Nietzsche, The Gay Science, 290 (1882)