Hit Windows key by accident. Boom. Back to entertainment OS.
Try to search for a file on your drive. Boom. Back to entertainment OS.
Launch a file with an extension still assigned to a shitty Metro app. Boom. Back to entertainment OS.
I could go on.... And all of that under-the-hood enhancement you mention isn't really in dispute -- but all of that didn't need to go under a fischer-price candy wrapper.
Press Esc, back to desktop. Click on the top left, back to desktop.
I have zero issues searching for anything on my computer. Fix your index locations.
So you have to fix your default programs OH NO!
I haven't launched a metro app since installing, either on purpose or by accident. I haven't used the "All Programs' feature of the Start Menu since 7 was released and I figured out I can just type the name of the app I want or the file I'm trying to open.