Windows XP was about the time I started moving away from Windows more definitively, even as a secondary OS. It was the product activation crap. My OS on my computer should serve ME, not be beholden to the vendor after I put it on. Of course, we didn't realize back then how bad things could/would get...
So for that reason, I'm not really nostalgic about Windows XP, or subsequent versions, the way some people are.
Although it is interesting to see what many now consider to be the bad ideas of Windows 8, get their start in "Neptune"...