There are plenty of questions/answers discussing when/where to optionally include animation in an app. Now it comes to the point, there is almost ubiquitous animation all over media. Even a few traditionally static media like print is receiving the animation touch- think the covers of many 3D blu-ray movies have the side-to-side 3D effect.
I suppose, this question may even touch on animation between scenes in video.
This question is specific to UI on web and in mobile apps. After one answer and further thinking about the UI/UX that I'm studying, it's better to consider this from a context where everything can be animated. There is at least one context, that is the case of games.
So.. when is animation really not preferable?