I just finished reading a last-century travel essay on Japanese trains by Sallie Tisdale, which inspired me to look up her web page, where I found this statement by her that I really like:
I only write nonfiction, the art form named for what it is not. Mostly I write from the first person, and sometimes you could call it memoir and sometimes the personal essay, though I don’t find a clear line between these forms. I used to think that the most crucial question for one who labors in this particular field is whether or not the work is true. Then I thought that perhaps a better question is whether the work is fair. I’ve come to believe that nothing is entirely true and little is fair. Everything I write is sinful, full of lies, especially the big one, the one you go to hell for: pretending not to be a fool.