No, folks aren't used to other people sitting around quietly with a glazed look in their eyes. But we, as writers, need to do just that. After all, writing is supposed to take place in the mind first. If you are forcing your brain to keep up with your fingers then you've got things backwards. His nephew asked what he was doing.
Writers look through windows.
That strip really hit me at the time. It reminded me that telling a story isn't only about getting it down. It's also about living it in your head, sorting through its parts, ironing out the flaws, letting it breathe. Maybe you're the kind of person who cannot think unless your fingers are moving. Writing a novel is, in a way, just daydreaming that's been whipped into shape and committed to paper.