It's not because you upgraded from Windows 7; a vanilla Windows 8 installation has the same desktop too.
In particular if you use the Windows 7 Start menu with the keyboard - typing in a name to search for it - that works much the same in the Windows 8 start screen. Some useful keyboard shortcuts:
* Windows+W to go directly to the Settings
* Windows+F to go directly to Files in the new start screen
* Windows+X to get a quick popup menu of power user tools
* Windows+I to open a panel of quick settings
If you want something more like the Windows 7 Start menu, try Start8:
http://www.stardock.com/products/start8/
I've been trying it out a bit and am not sure whether I prefer it or the Metro start screen. I very much like the lack of animation in Start8 - that was the main thing I missed from Windows 7.
One other subtle thing I miss from Windows 7 is that shortcuts to apps like Notepad will start multiple instances of the app. For some unfathomable reason, the Windows 8 start screen always goes to the first instance of the app if you try to start Notepad or the like multiple times. That would be OK but I can't find any way to override it and easily start multiple instances. Start8 brings back the old behavior here.
You can do that by right clicking the icon on the bottom taskbar and click the app to start. It did drive me crazy until I figured this out.
Middle click does work on my Windows 8 start screen; it always launches a new instance.
It doesn't do anything on my Windows 7 machine's start menu, though. But that's no problem because left click does what I want.
Testing a bit more... Now I see! In Windows 7, middle click works on the taskbar but not in the Start menu. In Windows 8, it works on both.
Most ubuntu users had a similar transition, when they moved from gnome to unity. It isn't that bad; or even at all.
(Classic shell still has the search feature. But often I launch apps before remembering their name - I'm a big user of apropos to recall commands. I remember locations. May be a difference in cognitive style.)
So I would say, if you are worried that it'll destroy your Windows experience as you know it, don't. It's still there. Really still there, with some minor improvements (e.g. task menu). If I didn't get this for free, I would have felt cheated (as in, this is just an UI skin over my existing Windows 7). What I miss the most is the start menu, and I guess I'll download some start-menu app to replace that.
I don't use my laptop as a tablet so I can't comment on the Metro interface, other than that it's fluid (like the Windows Phone). I don't see there is any chance I'd buy the Surface RT though... The App Store is very limiting at this point. But then, I am not their RT audience.