A person's faults are largely what make him or her likable. I like for narrators [of novels] to be like the people I choose for friends, which is to say that they have a lot of the same flaws as I. Preoccupation with self is good, as is a tendency toward procrasination, self-delusion, darkness, jealousy, groveling, greediness, addictiveness. They shouldn't be too perfect; perfect means shallow and unreal and fatally uninteresting. I like for them to have a nice sick sense of humor and to be concerned with important things, by which I mean that they are interested in political and psychological and spiritual matters. I want them to know who we are and what life is all about. I like them to be mentally ill in the same sorts of way that I am; for instance, I have a friend who said one day, "I could resent the ocean if I tried," and realized that I love that in a guy. I like for for them to have hope — if a friend or narrator reveals himself or herself to be hopeless too early on, I lose interest. It depresses me. It makes me overeat. I don't mind if a person has no hope if she or she is sufficiently funny about the whole thing, but then, this being able to be funny definitely speaks to a kind of hope, of buoyancy.
That's from her 1995 classic, Bird by Bird.