wow! very nice! I'm looking forward to the animation in Android L, and other visual improvements. I just lost my galaxy nexus, and that gives me the reason to get a new Nexus. hehehe.
With regards to transitions, windows phone 7 got it correctly first, and this is the direction Android is going. For every user touch, it gives feedback instantaneously (in the form of an animation). Might not be the result the user is expecting, but it shows up an animation that makes the UI feel responsive. He doesn't need to wait staring at a "non-moving" screen like what happens in some aspects of android.
thanks Pinyan! very informative.