I've been trying to like to KDE 4 since before its very first developmental release. I've been a KDE user since my first day in Linux, about the time KDE was at version 1.99 (the version that shipped with Mandrake 7.2). The buzz for KDE4 was humming quite loud and lot of happy users posted how nice it was. I kept trying it and was always so disappointed in not being able to like it. Besides the overall plastic feel, here are the top 10 things that drive me nuts with KDE 4 (and believe me they are just the top 10):
10. Everything is a "plasmoid." And most annoyingly, even desktop icons are plasma widgets. Not only is it fugly, but it also takes up valuable desktop space. It reminds of Windows 98 when I had to buy an extra program just to make the icon text background transparent.
9. Dual monitor separation - What I mean by that is on dual display systems, one has to configure each monitor/display/half of the desktop separately. And it also means that the panel can't stretch out over the two displays, move from one to the other, and you can't move icons from one to the other. They are really almost completely separate desktops. The only thing we can really still do is move windows between them. Thank goodness they wrote that in.
8. Akregator Unread indicator number - In KDE 3 unread articles numbers were bold and IN RED, which makes seeing feeds with new articles much easier than just this 'just bold' method now. If you pick out the right font it's not as hard to see, but some distros' default font make it very hard to see. In any font case, using just bold causes me to have to slow down and look a bit more carefully. My eyes are getting old and this is an inconvenience. I want my RED back!!!
7. Akregator pulls in random order - In KDE 3 Akregator would pull in the feeds in just about the order in which they are listed. But now, KDE 4 pulls in some random order that I've yet to identify. It's not alphabetical. This makes me have to wait until it's all done before I start down the list. Before I could start searching for good articles almost immediately upon clicking Fetch All. And Akregator in KDE 4 pulls in a lot sloooooower than in KDE 3. Again, loss of time and convenience.
6. Can't search for individual feeds anymore - One thing I've always wished for in Akregator is a "Sort feeds alphabetically," but in lieu of that, we could search for feeds by depressing the keyboard letter beginning the feed's name. For example, if I wanted to find tuxmachines.org in my list, I could keep hitting "t" as it went through the list highlighting each feed that starts with "t." But this functionality is now gone. So, with 1500 feeds, I'm shit out of luck trying to find a particular one inside of a half hour and a lot of effort. I usually just give up. Wouldn't it be nice to have a sort alphabetically or search function for the feed panel or at least have the highlight by letter back?
5. Dictionary widget needs extra clicks and less information - Now instead of the nice textarea for the Dictionary panel applet like in KDE 3, we now have this stupid icon that must be clicked upon in order to raise the input area. And the output is very limited now. Many times it just shows one or two short basic definitions instead of all the uses of the word and, equally or moreso as valuable to a writer with perhaps lesser skills, the extensive thesaurus at the end is gone. Perhaps they changed dictionary databases, but I don't see any way for the end user to configure it, do you? Basically the dictionary is almost useless at this point for anything beyond spell checking.
4. List of open windows too big and doesn't wrap - See how in this picture the list of open Konqueror windows seems to run on passed the top of my monitor? Well, IT DOES! With a monitor with a height of 1050 pixels, that leaves me room to see about 28 or 29 available windows, leaving the rest inaccessible. Taking about 40 pixels for each line in their efforts to make them all nice and shiny is ridiculous. Aaaaand, they don't wrap. In fact, that's the key. In KDE 3 when the windows list got too tall it would wrap, or stop at the top of the display and make a second column where I could still see them, click on one, and bring it above the other windows for use. I still ain't found a good work around  for this. In-con-ven-i-ent!!! <heavy sigh>
3. Kmail Wrapping Links - Oh, but the links in KDE 4 Kmail wrap! This is real nice for having actual clickable links - um, no. Now we have to highlight to copy, open a new browser, and paste into address bar. So, better make sure there is no homepage set or else there's another couple extra step added to the hodgepodge. Sometimes you can just highlight the wrapped part and click on the linkable part and the site will come up and you can add the extra part. This rarely works just right. Of course, they didn't wrap in KDE 3 which meant links actually worked in sent or draft mail. What were they thinking? Oh, what's that you say? Turn off word-wrap? Yeah, it's real nice to send folks unformatted emails, that won't annoy them at all. Or better yet, let's go into the configuration and change each time just for the ones with links.
2. Where the fsck is the Konqueror web history?! This one has pstops me more than once. This is a critical bug to users and yet it seems to be way down on the list of priorities to fix. I need it because the power goes off or blinks here quite a bit and the restore session doesn't work if KDE isn't shut down properly of course. So, not being able to look through the history to find my lost links really messes me up. Twice Thursday, in trying to find a work around  for number 4, my finger slipped off while the cursor was over "Closed" in the Konquoror taskbar right-click menu! grrrrr! I've been pretty lucky and so far KDE hasn't crashed out to the login yet, but I'm sure it's just a matter of time. And when it does - grrrrrr... Besides, sometimes a person might like to go back and just find something they saw earlier. This one  is just inexcusable.
Edit: I found a history - it's not in the sidebar, but up in the menu under GO. It opens up a separate little window, but hey, at least it's here. I don't know why someone didn't tell me about this! Anyway, I went off on it cause I googled around and all I really saw on it was the bug report about it not working and someone talking about the bug report being ignored. Sorry KDE guys.
1. Can't stretch wallpapers over two displays - This one is related to number 9, but was the number one and my first annoyance with KDE 4. Now I have to use a separate wallpaper on each monitor, or sorta "tile" the one across the desktop. This is a really ugly solution. Real ugly. Fscking ugly! I have so many cool wallpapers I've yet to use that are just wasted now. Of the below, which do you think is a nicer effect?
Bonus: nspluginviewer still broke - 'nuf said there.