Animations are hardly the worst thing about iOS7. After playing with betas for several weeks on an iPad 2, I, for one, have developed a cordial dislike for our iOS7 overlord. I've been trying to figure out why it feels so bad, and this is my pet theory:<p>In "Thinking, Fast and Slow", Daniel Kahneman talks of the two modes of thinking as System 1 (automatic, fast, involuntary cognitive processes like face/pattern recognition) and System 2 (conscious, attention-requiring processes like multiplication).<p>"System 1 runs automatically and System 2 is normally in a comfortable low-effort mode, in which only a fraction of its capacity is engaged. System 1 continuously generates suggestions for System 2: impressions, intuitions, intentions and feelings. If endorsed by System 2, impressions and intuitions turn into beliefs, and impulses turn into voluntary actions. When all goes smoothly, which is most of the time, System 2 adopts the suggestions of System 1 with little or no modification...<p>When System 1 runs into difficulty, it calls on System 2 to support more detailed and specific processing..."<p>A good principle of usability is to keep both systems humming in the manner described above, reducing "page faults" into System 2 to the minimum.<p>The realism and skeuomorphism of old Apple design (reaching godawfully kitschy heights in leather-stitching and reel-to-reel tape) with the 3-D buttons and shadows had this in their favour: they made it very easy for System 1 to parse the landscape. Navigating an Apple UI felt smooth and intuitive; never effortful.<p>But now, struggling through the anorexic fog of iOS7, I guess they've thrown the baby of usability out with the bathwater of realism. System 1 is often forced to fault into System 2 to make sense of patches of stark, undifferentiated space, a mess of thin fonts, single-pixel-wide, poor-contrast UI elements. The more attention you have to divert into basic navigation, the less you have to focus on the content. Most system apps (Notes, Mail, Calendar...) suffer from these issues. Plus the eye-wateringly terrible icons and saturated colors (seriously, who came up with the Safari and Game Center icons?) and poor readability of app names. Change the background image from the default of Dark Nebula to one with sand and the readability gets much worse. I waited to see if it was one of those things which you get used to, but no luck.<p>Not everything's bad: the layering effects, blur, control and notification panels sliding in from top and bottom are all great improvements from iOS6. But surely it's possible to create a UI which is navigable by System 1, which ruffles the minimum of aesthetic feathers with re kitschy realism? IMHO, Mountain Lion has done exactly that: Gradients, shadows and colors have acquired a quiet, subtle elegance which are a far cry from the days of lickable buttons.