I see it as there’s a lake and there’s a shed. The shed more properly should be called a workshop. But I’ve always called it the shed. The lake is just where stuff comes up out of and I’ve always imagined that there is something living in that lake that chucks me things. That just throws things up at me that I catch. And then I take them in the shed, and I work on them.

This is where things start getting a bit elaborate. When I read my own writing, and often when I read other people’s writing as well, I often think of it as there’s too much lake there and not enough shed. That wasn’t worked on long enough. At other times I think that a piece of writing is pure shed. You bang that up. There is nothing of the lake in there. 

The best writers, the absolute pinnacle, have an amazing lake and they have an amazing shed. Something that borders on a palace. They have amazing stylistic tools. They are amazing prose technicians, but they also have that bizarre ability to pull out the idea that no one else has ever quite done before. Or to extract the character who lives with virtually nothing done to it.
      - J.K. Rowling: On Writing - Part One (YouTube video).

. . .

The creative journey is both imagination and hard work.

Too much imagination and not enough hard work and the piece lacks clarity and focus. It risks being meaningless. 

To much hard work and not enough imagination and the piece lacks depth, uniqueness, perceptiveness. It doesn't tell us the artist's perception of truth. It lacks character.