Maggie O’Farrell turns the “write what you know” cliché on its head in The Guardian. She is right, I think.
Of her peculiar fascination with dysfunctional families, she explains, "I'm very close to both of my sisters, but I think a lot of writing is talking about something you don't know. I've always been intrigued by people who don't get on with their siblings; the idea that you wouldn't, and why that would be, fascinates me. Often, I think the impetus to write is to explore something you don't fully comprehend."