Windows 8 is so wholly different from Windows 7 that, to a non-technologist, it doesn't feel like improvement, enhancement, or evolution. The only thing that it feels is broken.

A non-technologist doesn't see a computer as a tool in the same way. If a non-technologist's computer "breaks" (and this can be anything from an actual breakdown to a window being one size one day and smaller the next), that user will get stuck. We've all seen perfectly competent users totally bamboozled by what seems to us to be the most simple thing.
An interesting point of view: Windows 8 moved the cheese, Windows Blue doesn't put it back | ZDNet