One of the marks of true genius is a quality of abundance. A rich, rollicking abundance, enough to give indigestion to ordinary people. Great artists turn it out in rolls, in swatches. They cover whole ceilings with paintings, they chip out a mountainside in stone, they write not one novel but a shelf full. It follows that some of their work is better than other. As much as a third of it may be pretty bad. Shall we say this unevenness is the mark of their humanity - of their proud mortality as well as of their immortality?
I have noted that, barring accidents, artists whose powers wear best and last longest are those who have trained themselves to work under adversity. Great artists treasure their time with a bitter and snarling miserliness.
Writers seldom choose as friends those self-contained characters who are never in trouble, never unhappy or ill, never make mistakes, and always count their change when it is handed to them.