One of the things that’s taking off massively at the minute (and for quite a while actually) is the use of animation. 24ways had a great article on how to animate, within it there is one gem of a tip that I just have to republish. It answers the question of how quick you should animate.
There is a rule of thumb in the world of traditional animation which is applicable to web animation: however long you think your animation should last, take that time and halve it. Then halve it again! When we work on an animation for hours, our sense of time dilates. What seems fast to us is actually unbearably slow for most users. In fact, the most recent criticism from users of animated interfaces on websites seems to be, “It’s so slow!” A good animation is unobtrusive, and that often means running fast.
When getting your animations ready for prime time, reduce those durations to 25% of their original speed: a four-second fade out should be over in one.
So when you are next marvelling at your great little animations think about speeding them up, if not 4 times faster maybe 2 times?