> Mixed metaphors, style over substance, and the idea that "flat" is anything but a way to turn your display into a sludge of rectangles of slightly different shades of grey with little or no differentiation between them, and few or no visual cues as to what elements of windows are clickable.

It isn't even that any more. Now you have "pills" and "Islands" of random rounded shapes completely disconnected from the context they are supposed to be impacting. things float above or next to things with no connection between them. Content suffers for fobs and exclusive sets (old timers call these radio buttons) or tabs are now just things that happen to be close enough that you should just know they're associated with each other.