[tomxor]

I totally get where you're coming from, most employment of CSS animate and transition is excessive and reduces UX.

The rule is that you should never have to wait for a UI animation - That said, UI animations done correctly, which are subtle and extremely short, do enhance perception of UI controls state and transitions. But I can't blame people for the broad hate towards animation on the web, so much of it is done poorly in a way that detracts from the overall experience.

[mrob]

I have only once seen a UI animation that I didn't have to wait for. This was in the Metacity window manager, which had an option to animate windows minimizing/maximizing using a wireframe of their outline that could not be interacted with. The actual window moved immediately, and the wireframe did not obscure much of the screen while it moved. I would still turn them off, but if every UI animation was designed like this I would dislike them less.

[anderspitman]

That is a great design. Shows you where the minimized window is (in case your brain missed it) without making you wait. I would love to see an entire UI designed around the principle of "don't make me wait. Ever."

[mcbits]

I think the best rule of thumb for UI animations is to keep speeding them up until users stop praising the beautiful/elegant animations. They shouldn't notice the animations.

[Gigachad]

I think iOS does an extremely good job at animations. They help convey movement/what changed/where did I just go, but they are usually so fast and subtle you don't realize there was an animation unless you try hard to spot them.