They messed up the user interface. They should have perfectly seperate the two UI's or put Metro into desktop and not the other way around. Now thet frustrate all desktop windows users (billions) to provide a nice touch interface for a few tablet users.

On top of that they added another layer of multitasking to the already cluttered windows experience, and they force the user to open metro and go through hoops to open an app on the desktop, where they already are.

I think that after 2003 all the UI decisions of Microsoft are plain wrong. Changing things that are proven to work for the sake of change.