Three words: UAC.
I don't recall the specifics, but I was trying to execute a command/program/process that comes automatically installed with Vista and it asked me "Are you sure you want to do that? This might cause harm to your computer". It damn well better not.
Then I noticed it doesn't seem to have a "yes to all" feature like XP did, but I admit I don't do much that lets me run across it. I was copying some pictures I took from a trip onto a flash drive and it was copying without the properties for some reason (which where there when I plugged it into my XP machine). I had to click "yes" for every single photo, of which there were about 75 that didn't get their properties copied. Oh, and the UAC goes apeshit on me and darkens the rest of the screen so if I, say, tell it "Open MSWord" while I'm doing something important in another window- maybe having a chat with a friend or playing a game or working on a paper- it'll stop me while I tell it "Yes, you fuckwit, I want to do what I just told you to do or else I wouldn't have told you to do it."
The window previews are pointless, as they're too small to really see what you're doing that you can't tell by just not having 50 windows open at once and remembering sort of what you were doing in each window. Or just clicking it and finding out without squinting your eyes, I mean, your mouse is already there, just click and save your eyesight, unless you're already a microscope.
It's a system hog, though if you have a good desktop this isn't as much of an issue, I grant. Though, Vista, out of the box, came with what was either five or ten million more lines of code than XP with all of its service packs (I think it was 50 or 55 million, but I don't recall the exact numbers). Though Mac OSX is ultra-guilty of this, coming with 86 million lines out of the box.
The source code was totally redesigned (contributing to the above issue), and so a LOT of stuff that would work on XP, which had the nice little "if it worked on ME (which was pretty bad)/2000/NT/etc it'll work here" for almost everything. Vista has the "Well if I don't ask you to confirm that you told me to open MSWord today, it might work if you're a redhead." Things that were compatible with XP don't work at all on Vista, so a lot of things have an XP and a Vista version- two separate data packs. However this is only a real problem for people who copied the entire contents of a previous hard drive- programs and all- or businesses looking to switch from XP to Vista.
Minimizing has the annoying "fade out" thing that gets piss annoying very fast to someone like me.
Now, I grant that I don't have a ludicrous amount of experience with Vista but I have used it quite a bit, though my XP machine is my main one (it's what I've been using for a while now so it's got most of my data on it).
BUT, on the whole Vista works fine. Most of what I've encountered are either more annoyances than anything else or fairly rare. Vista runs fine, but my user-end experience has just been that XP runs smoother.
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