I’ve been hacking on rich UIs with animations for a few years—both in the litl OS and in my pet project. There was a time, not too long ago, that doing animations in your web, mobile or desktop app was not so common or convenient to do. You had to mess with weird lower-level APIs or write a lot of cryptic ad hoc code. We just didn’t have nice high-level APIs for animations.
Nowadays fluid UIs with animations are relatively easy to do on pretty much all major platforms out there—jQuery, Clutter, Core Animation, WPF, QML, Tweener, etc. Things like fading, sliding, zooming, rotating, scaling are all just a few of lines of code away. So it’s very easy to fall on the trap of overusing animations just for the sake of eye-candiness. But animations can have a very negative impact on the user experience if not done properly.
Using UI animations often means that you’re making your app take more time to go from state A to B. For example, by using this ribbon-like effect on modal dialogs—motion mockup by Jakub Steiner—instead of just popping them up immediately, you’re adding a delay between the user request and the dialog being ready for interaction. The animation in this case is not a bad idea as it helps the user understand the UI and it’s fast enough. But if you consistently delay interaction with animations for no good reason, the UI quickly gets very annoying to use. So, getting the timing of your animations right is very important.
When animations are not subtle enough, they cause users to move their attention from the current task to the animation itself. It’s like the UI is saying “Look! I’m animating now!”. Google’s particle similator logo is an extreme example of a distracting animation. Every time you add an animation just because you can or because it’s “cool”, you’re probably just distracting your users.
Animations might actually confuse users. One recent example is the Twitter for Mac’s continuous slide out transitions that create a strange sensation of infinite “stacking”. Confusing animations might seed wrong assumptions and uncertainty about how the UI works: “Why does it slide to right again when I click on the previous tab? Am I doing something wrong?”.
Certain animations look cool on the first few times you see them but become quite annoying later on. The repetition problem is aggravated when the repetitive animation is also confusing, distracting or delays interaction. For example, the tooltips animation in MeeGo’s Netbook UX is both repetitive and distracting—Intel guys are aware of this issue. Commonly used UI elements should have very subtle or no animations at all.
And I guess there are many other ways animations are just done wrong. Bottom line is: with all the simple ways of filling your UI with all types of animations these days, it’s quite easy to end up overusing them. Resist the temptation! Animations work best when they highlight the underlying mental model of your software and improve UX. Animate wisely.