@Garulon: The fact that you are having to explain how Windows8 works means that Windows8 has failed to be intuitive.
A good UI is like a good joke - if you need to explain it, it isn't very good.
Let's not mistake Dr Herbie's failure to find the power-off button as a request by him for help or as an indication of his inexperience at Windows8. The job of the UI is to enable users to find features in the app.
Since Dr Herbie had to use a different program to find the power-off feature, the Windows8 shell UI team failed on the objective measure that they had a feature that Dr Herbie couldn't find using their interface.