[DidYaWipe]

And controls were demarcated as controls, not disguised as plan text or a decoration. You could tell if a function was activated by looking at the outline of the button; if the "bevel" shadowing went inward, the button was depressed and the function was on.

"Flat" design is simply derelict design. Fortunately there has been some backlash and we might be returning to legitimate GUIs.