At WWDC, I listened to Apple representatives make some excellent points about taking the time to build a 100%-compliant Aqua application, and I think all developers need to look beyond the code and listen to what the folks at Apple have to say

Adhere to Window Models. Document windows, Utility windows, Click-through, Layering, Drawers, Controls. How do users open windows, how do you properly title windows?

Other examples of these animations might be to show the status of an FTP transfer, the progress of media being digitized, or an updated time signature. And don't forget that users may want to have some control over this, so give them plenty of options, including the ability to turn these functions off.

You Must Promise. To call your mother, to help old ladies cross the road, and to turn your cell phone off at the movies.