I know there are writers who like to say that every novel is hard, and it doesn't get easier. That may be the case, and I've only written two. But the first, to me, was characterized by an enduring oscillation between perseverance and a profound doubt.
If you think of all the enduring stories in the world, they're of journeys. Whether it's 'Don Quixote' or 'Ulysses,' there's always this sense of a quest - of a person going away to be tested, and coming back.