Being mostly a KDE user, I don't know why everybody hates GNOME 2, can anybody explain this?
It's Gnome 3 that gave rise to a lot of bile, not Gnome 2. Gnome 2 on the whole was pretty popular.
Gnome 3 has actually come on a long way too. Its big problem when it first appeared was that it removed lots of important functionality, because the developers thought that they knew better than the users, and although the users wanted them, the developers were of the opinion that they *shouldn't* want them. Suddenly all the things that made your desktop a constructive work environment were taken away, and to begin with at least, complaints were ignored.
Over time though it has got better, and there are features of it which I now really miss when I'm using other desktop environments. There a still some really stupid design decisions, and bits that work worse than in earlier versions, but it's got back to being usable.
A few examples of remaining irritants in Gnome 3:
* If you suspend your laptop, then resume, the network manager prompts you to ask whether you want to reconnect to the WiFi point which you were using before. Why? It doesn't prompt you at boot, just after a resume. Yes, of course I want to carry on using the WiFi I was using a moment ago.
* By default, if you drag a window to the top of the screen it causes the window to be maximised. Yes, I know they copied this from some other desktop, but it doesn't make it any less idiotic. It's overloading a gesture to do something different, and leaving you no way to do the old thing which the gesture used to do. It doesn't even make it any easier to maximise a window, because you could always double click on the title bar to achieve the same thing. It does however mean that if you want a number of tall windows (making best use of your large monitor) you have to jump through hoops to achieve what should be easy.
Doubtless others can provide lots of other examples.