Hmmmm... I have to admit the latter does sometimes happen, usually late at night when I'm writing and my mind takes off on me. I'll start laughing
(or get emotional) thinking of something a specific character would do that I hadn't even
considered before then.
However, even when I'm not writing, I'm always working. I go to sleep thinking about my novel, I wake up in the middle of the night to jot down notes, and I carry blank index cards with me wherever I go.
I'm always writing something down I've seen or overheard or thought of that's relavent to the book I'm working on at the time. Then, at the end of each day, I stuff everything into
a twelve inch-high aluminum garbage can labelled 'story ideas' (index cards, photos, articles I've cut out of magazines or newspapers) and every few weeks I'll dump it out and go through it, taking what I want and putting back what I've decided to reserve for another novel.
It might seem like an odd process, but it works well for me!
