I've said this before here, but Apple have really concentrated on the laptop experience at the expense of the desktop experience. Which is understandable if you look at their sales figures. I was using a Mac Mini when I first upgraded to Mountain Lion, and really wasn't a big fan. Then I got a Macbook Air, and all of a sudden all of the modifications made sense. Things like the fact that they have optimised the OS for SSDs - which you find in laptops, not desktops. But that optimisation makes hard-drive based Macs much much slower than they were before. Or the fullscreen interface which works really well when you can do a three finger swipe to swap between screens, but not so well if you have a mouse.