Reading Woolf's diaries and letters alongside her novels changes the novels. The novels are highly crafted and the crafting is visible — you can see the work. The diaries record the work, including the parts that didn't succeed and the days when the whole project seemed wrong. The diaries are full of anxiety about whether what she was doing would work.

This is useful for any reader who admires a writer and imagines the work flowing easily. It didn't. The Waves required multiple false starts and a complete structural overhaul midway. Mrs Dalloway was rewritten from a short story. To the Lighthouse was written while Woolf was uncertain whether the form she was using was legitimate.

The anxiety is not failure. It's the cost of attempting something that doesn't have a template.