I’ve used Windows since version 1 (the original tiled window UI). Since Windows 3, the thing I’ve liked best about Windows is the ability MSFT provided to replace much of the Windows UI.
I hated Program Manager (pre-Windows 95), so I used Norton Desktop. I used Windows 95 briefly, much more Windows NT4, and I got into LiteStep and its themes, which lasted me to the end of Windows XP’s days. (I still use a very minimal LiteStep theme in my XP VM.) LiteStep stopped working adequately in Windows 7 (I skipped Vista), so I switched to the even more minimal Emerge Desktop. Since Windows 8, I’ve been using Classic Shell.
I have to give MSFT credit for letting me replace most of the Windows UI, replacing it with what I preferred. If Windows 10 S means the end of customizing Windows, I’m going to avoid it if possible. I value the flexibility MSFT has given me heretofore. I don’t want to see it end. Sadly, that seems to be the path MSFT intends to take.