Believe it or not, the largest part of your world is not what your audience sees but what they don’t see.
As I explained in my last post on world building, your story is the lens through which your audience sees the world you’ve created. Consequently, the parts of your world that the lens does not see remain unseen by your audience. Since your story reveals only a small sliver of your world, this means that the vast majority of your world will remain unseen.
Your story won’t visit every single village, hamlet, or community in your world. It won’t get to introduce every living being in your world. It won’t get to pass through every wilderness or describe every landscape. A believable and compelling world is just too vast and complex for that.
So what’s the point in creating something that your readers will never see? Even though it’s tempting to leave these unseen parts undeveloped or cut them out altogether, you would only be hurting your story if you did.
The reason why we develop these unseen parts is that they support the parts that are seen.