For me Windows 2000 Professional is the best OS that Microsoft ever released. At the time I used it was really polished, stable and fast.

One recurring question that I keep asking myself is why UIs have to constantly change for the worse?

What would happen if vendors kept using the same UI for decades? Would people hate or love having a one well thought UI?

> One recurring question that I keep asking myself is why UIs have to constantly change for the worse?

So the designers have something to do and so the CEOs have something easy to think of when they need to 'shake things up'.

That's all I can think of. I can't think of any that actually benefit the user (barring your original UI being absolute garbage, to the point anything else is an improvement, but even then, the original UI should still be available in some capacity).

> What would happen if vendors kept using the same UI for decades? Would people hate or love having a one well thought UI?

They hate having to re-learn UIs every 5-10 years (per OS/application/website!), so I don't think you've got much to lose trying to maintain a single good UI. And in the few cases where the UI basically hasn't changed in a long time (XFCE, VLC, probably more), they fucking love it.