Worldbuilding, for me, is a long-term process. I'm kind of in awe of people who can just wing it-- start with some sort of High Concept, and go right to the writing, discovering the world as they go. I could never do that. And I'm sure some people are "build what I need, figure out the rest later". Again, I'm glad that they can do that; it doesn't work for me.
In fact, more often than not, I'll start the process, build stuff and go, "This is all wrong". So there's nothing else to do but tear it all down, then use the previous work as a platform to build something better.
When I first started my Space Opera setting, I had some initial concepts of humans in space, some alien races, and got to work on that. I mapped out a munch of human-colonies, the space around those, etc. And then it hit me: I have this mishmash of colonies and other worlds in star systems in close proximity to Earth that bear no relation
to the actual star systems in close proximity to Earth. It'd be like doing a story in which swampland and desert are found right outside New York City. So I tore it down and rebuilt.
Right now, I've got something cooking that I'll just call Secret Project MSD. It's very far away from being a thing I can really talk about, let alone have an actual sellable story. And part of that is I just realized the worldbuilding was extremely flawed. Short version: I started with a basic thought experiment as the high concept for the world, and took that to the next level. And yet, at the heart of it-- the central characteristic of it-- there was still a very Brit/Celt/Western Europe core that I should have escaped from. I'm not sure why I did that, other than thoughtlessness.
Especially since cutting that stale core only helps the overlying high concept. Digging through those bad presumptions, I'm finding something far more intriguing, far more exciting to me. And that may be why, despite having a fleshed out outline, I wasn't going any further with this particular project. Deep down, I knew there was something stale and uninspiring about it.
So I tore it all down. The outline can stay-- it's solid-- but many of the worldbuild presumptions will have to be re-examined, re-built and made better.
What's funny is how hard it can be for me to get this idea in my skull. At one point, before I made the realization to rebuild the culture stuff in the center, I actually thought to myself, "It's a shame I can't have X in this world, because I've already established that this is Y."
As if the worldbuilding work I had done-- no significant storywriting beyond a few thousand words and outlines of the whole project, just worldbuilding work-- was so set in stone that my hands were tied. Which was some crazy thinking.
I know part of that is my mindset that writing it down makes it real, so even knowing that I can tear it apart and build it up again is something I rebel against. Right now I'm also updating the world map for the Maradaine setting, and as I do things like clean up the coastlines (because the version is so old the coastline is blocky pixels), I still imagine the reality shifting under the feet of the people who live there. Some fishing village gets eradicated by the hand of God when I move the photoshop eraser along the coast.
But sometimes that's what you have to do to break out of bad patterns and write something more interesting.