I'm still annoyed by windows 7. Being used to win XP on my good-old PC, I bought a laptop and it had this abomination on it.
Taskbar windows? Oh, no, forget that, that's old. How about icons instead? Have a bunch of firefox windows open? Just push the firefox icon and scroll between the windows till you find the right one. How is that more simple? It's actually more complicated!
And what's that on the desktop? A bloody clock? I don't need it, thank you very much, I have one on my wall. And what's that thing that keeps popping up? Media tools? If I needed them, I'd open them myself.
Everything is so "cool" and "shiny". Wow, microsoft, you rock. IT'S ALL PAIN IN MY EYES