John Gruber, regarding the “simplicity” of iOS:

The utter simplicity and obviousness of the iOS “system”, from a user’s standpoint, is arguably the primary reason iPhones and iPads are so popular. Is such simplicity for everyone? No. Is it suitable for all computers? No. But it is both comforting and comfortable for everyone who’s spent the last two decades more confused than not by their computers.

The utter simplicity of the iOS home screen is Apple’s innovation. It’s the simplest, most obvious “system” ever designed. It is a false and foolish but widespread misconception that “innovation” goes only in the direction of additional complexity.

Innovation Through Simplicity