I used to get irritated by every new release of Windows, because it was "different". But I've found, over the years, that if I just suck it up and roll with it... I generally end up liking the changes better.
I still believe one of the reasons most people hated Vista is that it was different from XP... but liked 7 because it was almost identical to Vista.
I run Windows 7 at work and Windows 8 at home... I like Windows 8 a bit better because it's faster, but I also learned (after trying to roll with 8 for a while) to just install Classic Shell and get the start button back. That truly was a mistake on Microsoft's part.
I find the latest version of MS Office to be absurd. Whoever designed the UI needs to be taken out back and shot. Example - if you're in a document in Word but want to open another... you click File->Open. Your whole screen disappears and you come to a new screen that shows your recently opened documents. Then you have to click "computer", where it shows you recently opened documents on your computer. Then you have to click "browse" before you FINALLY get a folder window to let you see your drives/folders. And if you want to exit out of this nonsense, you have to click the back button at the top left of the screen. It looks like MS Word opened up a whole new window because your document has disappeared, but if you click "close" or the Windows X button, it will close MS word completely... when did a back button become standard on a UI?
It's completely confusing. It seems designed for idiots who don't know how to use a computer - and (forgive me Apple people) I think MS is going after the Apple "need to be told each day how to tie your shoelaces" crowd you have no clue how to use a computer. But for someone like me with organized folders on his computer, it's a huge PITA.
Lots of other examples too. It irritates me when I look up how to do something and it says "swipe in from the right side, and type 'networking' in the search box". I don't want to have to search for everything, I just want it logically located in a control/settings folder like before.
And speaking of which, why is MS always moving stuff around the control panel? Every different version has a different location and method of setting up networking. Infuriating!