I’m always a bit wary when a writer says “it came to me in a dream!”
Stephenie Meyer is the obvious example of an author who credits her subconscious with the premise of her most famous work, Twilight. (Bella and Edward came to her in a dreeeeam!) However, Meyer is far from the only author to use her dreams as the basis for her fiction.
Indeed, it’s tempting, upon awaking from a particularly atmospheric dream, not to view it as an amazing story idea. After all, it feels like the hard work has been done for you: a vivid otherworld has been conjured by your dream; energising or moving or scary in a way that the best fiction can be. Why not accept this gift from your subconscious? Don’t invent; just transcribe. Simply embroider around the edges of your dream and voila! Great fiction!
Unfortunately, it’s taken me a terribly long time to realise that: atmospheric =/= good fiction.