There’s a really quick, fairly objective way to tell if your UI sucks. Google:
It’s clear that more people are having trouble with more fundamental problems in Windows 8 than in Windows 7. Closing apps, shutting down, and finding programs are pretty central tasks in day to day computer. Over time, these autocomplete suggetions will change, but for now it’s clear that a lot of people using Windows 8 don’t know how to do the tasks they are familiar with in Windows 7.