Not surprisingly, seeing as writers lie for money, we lie to ourselves all the damn time. You start off pretending a project doesn’t mean that much to you, or that you’re writing it to learn, or that you’re writing it for art, or that you need to do something during your lunch break. You tell yourself that your book is genius, that you’re a genius, that if not this book, then the next one. You send stories or novels out and start getting in rejections, and that’s the icing on the lie-cake — maybe my protagonist looked like that editor’s ex-wife, maybe I formatted it wrong, maybe space opera isn’t in (again) this year.
Because on some level the self-denial does protect you, and you need it to survive.