This has made a lot of people very angry and been widely regarded as a bad move.
Seriously though, this is the first properly good UI for a desktop computer. Mac OS (or I guess Macintosh OS at the time) was okay, but reliant on the global menu and weird drop-downs. Windows kept everything self-contained. Even multi-window programs tended to use the "multiple document interface," i.e., windows inside windows. Tabs weren't really a thing yet.
It also crashed if you looked at it funny and had the antivirus capabilities of warm cheese. But there's damn good reasons Windows 7 was the same experience, extended, rather than replaced. It's more-or-less what I style Linux to look like. And in light of that I'm kinda pissed off any OS ever struggles to remain responsive, when this relic ran smoothly on one stick of RAM that's smaller than my CPU's cache.