Transitions in windows resize, dialogs or message boxes.

While now we have the opportunity to have a 3d accelerated desktop, all we had created was 3d desktop switcher, shadows and menu fades.
But we aren't using it to create a best user experience.

Now we must use this to improve the things like the rude animation of the update manager when we click on the arrow to see more information, or when appear a Save dialog of Gedit.

I think that we can take as an example of the improved experience that create these effects in Mac OS X, with its animations in the System Preferences window or the Sheet style dialog in the programs.

All this makes easier to understand what dialog of what windows I'm searching or to continue with customizing the preferences without lost me between the popup windows.