Memoir
Memoir is a really tough category for some copyeditors. One can't just "apply the rules" and go forth. I mean, aside from the fact that there are very few rules in the first place. To copyedit memoir well, you have to be kind of zen and really let the author's voice shine through, often at the expense of beloved spelling and grammatical conventions. It's the author's life story, sometimes told at great personal risk, and it needs to be in his or her unique idiom. For all you memoirists who don't care about "who" versus "whom," I hear you. And I won't fix what's not broken.