On my current Linux Mint install (which is less than a year old and not heavily customized), my /etc/apt/sources.list.d has the following line:
deb http://security.ubuntu.com/ubuntu/ raring-security main restricted universe multiverse
I'm going to say this person's working with outdated or incorrect information, and/or security.ubuntu.com somehow got removed from his local installation.
Then I go back to Linux for something and everything I used to know is now completely useless.
I admit I haven't gone to Windows 8. I owe myself a new laptop and I just have this feeling of dread about that.
Also, clicking on the "volume" icon should not bring up a spinning blue circle, not even for a millisecond.
I just might get chased into a MacBook or whatever they are called these days. And I don't like Apple very much right now so that's something.
I had to expend a lot more mental energy last time I tried to use modern Windows, and has OS X got a maximise button yet?
--edit-- I'm not trying to say "My OS is better than your OS" because we all know where that leads. I just don't think anything is perfect and it likely comes down to what you're used to.
Gnome configs are only an issue if you still use gnome :)
In general things are moving to a more "it's all done for you" way of doing things, with less reliance on config files and unix file permissions and more dbus, service-oriented stuff. Personally I'm not a fan of because when things go wrong they go wrong in very, very opaque ways (try using the 'slim' display manager on Ubuntu 12.04 if you want an example).
At some point someone will probably come up with "CurmudgUX" for people like me that think the new levels of system-component integration will only lead to future pain, avoiding systemd, dbus et al. Guess we'll see.
See, that's the problem. The old system is abandoned and I have to decide "is it worth learning the brand new system?" Keep in mind this brand new system will not be used in 5 years, either.
I also don't sit around watching the forum discussions so when someone says "oh you need to uninstall gnome and install farknootz" I just say huh.
On Linux at least we have choice.