The thing is, flat UI worked really well on the phone, which it was designed for. It's just that some idiot manager came up with the "unified experience" idea

The thing is, flat UI worked really well on the phone, which it was designed for. It's just that some idiot manager came up with the "unified experience" idea and shoved that shit onto desktop Windows without any time for polish. Ironically I think pretty much anyone's first experience with metro was Windows 8 on PC, which was such a disaster that people wouldn't even give Windows phone a try because it had the same UI that they learned to hate. Not to say this is the reason Windows Phone failed, but probably one of the many factors.