When you start writing, you have your characters on a...

When you start writing, you have your characters on a metaphorical paved road, and as they go down it, all these other roads become available that they can go down. And a lot of writers have roadblocks in front of those roads: they won't allow their characters to go down those roads. I've never put any roadblocks on any of these paths. My characters can go wherever they would naturally go, and I'll follow them.