"The only really good piece of advice I have for my students is, 'Write something you'd never show your mother or father.' And you know what they say? 'I could never do that!'"
She's commenting on the close relationship young people today often have with their parents, but this closeness can breathe an eagerness to please not only the parents themselves, but authority in general. Moore's writing sometimes conveys a nasty view of humanity, one that would surely sadden any mother or father, but the nastiest parts are often the most funny and true. Insofar as it encourages students to stop trying to make people happy, Moore's advice is great — readers, like all humans, don't necessarily know what they want, and trying to please isn't a very good way of actually doing so.