Yeah, it was butt-ugly. The default Windows UI didn't actually look better until Windows 7, but I used the "Classic" look as long as it was supported. I skipped Windows 8/8.1 entirely, and while Windows 10 was reasonable in terms of how it worked, it was also butt-ugly, but now you couldn't do much of anything to customize it.
Windows 8 was stupid with the tablet-optimized UI, but I thought it was OK aesthetically, and Windows 10 more so. Even Windows 11 is "pretty" if you don't click the wrong thing and get a legacy dialog from 1...∞ versions back.
I use Linux by the way... but not all Windowses look ugly IMO.
There is a German saying "Grün und blau schmückt die Sau" ~"green and blue grace the pig" - and XP was green and blue and shiny like hard candy.