The goal is not to make your user interface as realistic as possible. The goal is to add those details which help users identify what an element is, and how to interact with it, and to add no more than those details.

There’s no complex mechanical mirror assembly swinging upward when the shutter opens. No matter, though. The cigarette box sized camera burps out a faux ka-click anyway. The mechanism producing this noise was quite necessary for its predecessor, the SLR/DSLR camera, but now functionally irrelevant in the newer point-and-shoots. This design cue (audible in this case) inherited from an ancestor is referred to as a skeuomorph, and they can be found everywhere in our daily lives — air intakes on the electric Chevy Volt, window shutters that don’t shut, copper cladding on zinc pennies, nonwinding watch winders. Even the brown cork-pattern on cigarette tips is a holdover from the days when cork was used as a filter.

In other areas, the improvements are questionable at best. Graphical user interfaces are typically full of symbols. Most graphical elements you see on your screen are meant to stand for ideas or concepts. The little house on your desktop isn’t a little house, it’s «home». The eye isn’t an actual eye, it means «look at the selected element». The cog isn’t a cog, it means «click me to see available commands».

The underlying secret to beautiful user interface design is realism: making 2D objects on your screen appear to sit in 3D space with volume, surface properties and undulations that might appear in real life. These faux 3D objects have highlights and shadows just like objects on your desk might have, and they have textures that emulate real objects from glass to sandpaper and everything in between. Designing beautiful user interfaces has more to do with the why than the how.