Flaubert keeps things understated in letter to George Sand, December 1866:
I expressed myself badly when I said to you that "one should not write from the heart." I meant to say: not put one’s personality into the picture. I think that great art is scientific and impersonal. One should, by an effort of mind, put oneself into one’s characters and not create them after oneself. That is the method at least; a method which amounts to this: try to have a great deal of talent and even of genius if you can.
More how we work.