Not all animations are useless. Actually, any useless animation has no place in the UI. - Some animations can be overlapped with time-taking tasks to keep user

Not all animations are useless. Actually, any useless animation has no place in the UI. - Some animations can be overlapped with time-taking tasks to keep user engaged but waiting at the same time. I think iOS does that when switching to an app that was swapped out to the disk. Loading takes time, so the animation compensates for some of the delay while the app's resuming. If there was no animation, the user could think that they didn't perform the action correctly, and might be inclined to repeat it, causing frustration. - Some animations are necessary to orient the user in UI flow. For example, the minimization animation moves the window to the icon that user needs to click in order to restore the app. The animation also makes user differentiate between close and minimize operations. - Some animations are necessary to give user proper feedback while keeping the responsiveness. One example would be the spring animation you get at the end of a list when scrolling using a touch screen. If there was no spring animation there, user would have no way to know that if that was the end of the list, or the touch screen stopped working.