"I've come to understand that the quality of memorability and inevitability which I assumed came from intense pleasure may actually have come from a kind of pain. That is to say that one learns from Nietzsche that there is something painful about meaning. Sometimes it is the pain of difficulty, sometimes the pain of being set a standard that one cannot attain."
January 1, 1970
https://en.wikiquote.org/wiki/Friedrich_Nietzsche