At first look, flat design always look appeasing, because it can be easily processed by your brain. Color and space are pretty much the only thing separating the elements. Skeuomorphism, however, requires your brain to process a lot more information: color, space, shades, contour, shadow, etc …
It’s simple why people like flat – it’s easier to understand. It’s like asking your brain to process two codes, where one is fast, and the other slow. Fast wins, right?
But things start to change when you keep going back to the designs. Gradually, you start understanding, and appreciating, the detail of skeuomorphism. There are many layers which separate the button from the background – shadow, color, gradient, border … Your start to understand that each has a role to play, and together they give a unique individuality to the button.
This is the thing with skeuomorphism: it grows on you as you come back to it. Flat design doesn’t. It offers you nothing more than what it did the first time you came around.