[ryanac]

Drag and drop. When I drag an icon to a location and I miss, I think it's better to see the item animate back to it's original location rather than just disappear and "pop" back.

Having it animate back is just better communication for that particular interface.

You can see this on Google Chromes new tab "Most Visited" page, drag an item and let it go on nothing, it will animate back to its position.

Then there's sorting, it's much better (to me) when the interface animates to show you what the effect of moving one item to a new location will have on the rest of the items in that list, you can see this effect on sites like Trello when you drag around cards, etc.

I'm sure there are more examples of good uses of animation in interfaces.