Mary Karr said we have to write about what we really are and what we have to write about, not what we'd like to write about:
“It’s difficult to accept what your psyche or history dooms you to write, what Faulkner would call your postage stamp of reality. Young writers often mistakenly choose a certain vein or style based on who they want to be, unconsciously trying to blot out who they actually are.”
Norman Mailer said that we write about ourselves and about others:
"We write novels out of two cardinal impulses (other than to make a living and the desire to be famous). One is to understand ourselves better, and the other is to present what we know about others. Of course, it is often impossible to comprehend anyone else until one has plumbed the bottom of certain preoccupations about oneself. That is why the writer is always at risk of using his or her talent for therapy – which can be closer to creative inanition than to art."
Jacob Needleman said that we write about our tensions and contradictions:
"The teacher makes room for the pupil to exist consciously in between the two natures of man. Similarly, the great sacred literature and art of the world, at its level, creates palaces and worlds of room for the individual person, the spectator in his flesh and blood moment of now, to become aware of the mysterious co-presence of two opposing forces in the world and in himself. Sacred art, like sacred life, is the mysterious blending of these two elements of cosmic reality, a blending that cannot be conceptualized or analyzed by the ordinary mind. It is the 'navel' in all sacred stories and myths and above all, in all sacred action of spiritually developed men and women."
Norman Mailer. The Spooky Art: Thoughts on Writing. New York: Random House, 2004. pp. 126-127.
Jacob Needleman. Why Can't We Be Good? New York: Jeremy P. Tarcher/Penguin, 2007. p. 231.