Windows 2000 was also one of the most consistently designed versions of Windows. XP also introduced tons of design language chaos as they only migrated some of the UI over to the new controls and left big chunks of the OS to languish. I think Control Panel had widget rot well into Windows 10 (Maybe still has this issue?).
I only grudgingly moved to XP and shortly after switched to Desktop Linux full time.
> I'm still rather baffled about how people look back fondly on XP
XP was the first consumer version of adult (non-w95 based) Windows. Relatively few people used Windows NT or Windows 2000. If you are one of the many people who's Windows use either started with XP or you went from W95 to XP, then XP was clearly the best Windows you've ever seen.