For me, it just came down to how unintuitive and slow Windows's desktop environment is. Setting up the most basic customizations requires going through like 15 sub-menus or dealing with the registry. Also, GNOME and KDE are just so much prettier than Windows's desktop environment.
This is it for me, too. Back before I got into Linux I was forever tinkering with third party stuff to try to make the UI more efficient with things like Enso and Docker, and make it prettier with other stuff, but it was always a ramshackle cludged together mess. GNOME just resolves all of those issues neatly for me, runs faster, and isn't crammed full of bloatware ad crap like modern versions of Windows. And it's more secure, free, and ethically satisfying as a cooperative, trans-national project.