A tradition rooted in the mythology of romanticism and its conception of the artist as a cultural hero would want to believe that everything pertaining to the life of a genius has to bear the mark of the sublime.
Everything in their lives -gestures, decisions, personality traits, eccentricities, even the most dissonant mistakes— are thus transformed into esthetic substance. We would want their lives to be masterworks, a perfect coherence— and continuity between the work and its creator.
Roland Barthes has criticized this conception as a basically bourgeois aberration — the perennial realism of the bourgeois culture, its need to identify the signified with the signifier. And then we learn about the real human dimension of these heroes— their pettiness, narcissism, avariciousness, arbitrariness, and childishness, all of which are no more than their human specificity. We are scandalized; either the work or the figure lies.
A harmonious painting, a novel or masterful symphony cannot possibly be the product of a person capable of such spiritual smallness. Then we are left with two choices—to dismiss the work as an essentially hypocritical utterance, or to disqualify the creator as the accidental author of some work that happened to be marvelous but was simply by virtue of a great skill, not supported by an equally admirable human quality.