In my opinion, Windows 8.0 and 8.1 are just awful, ergonomically. I don't know what drugs the folks at Microsoft were using when they did the user interface on it, but it seriously sucks. It seems that Windows 7 is the last version that makes any sense to someone who isn't also a heavy abuser of harmful, mind-destroying drugs.
My sense is that they were trying very hard to come up with a unified user interface that would work equally well on either a traditional desktop-type system, or on a mobile device such as a tablet or a cell phone, and they ended up with something that works very, very badly on either type of platform. I think the basic idea is valid, but in this case, the execution was very bad.