I've only ever seen one unintrusive animation in UI, which was the window minimization animation of the Metacity window manager. It minimized the window immedia

I've only ever seen one unintrusive animation in UI, which was the window minimization animation of the Metacity window manager. It minimized the window immediately, but then followed up with an animated outline showing where the window had gone. It was thin enough that you could easily ignore it, but still provided all the benefit that designers claim from their slow and disruptive animations.