I <heart> when some software, be it Ubuntu's desktop, or Android's various UIs, draws something that is some cached old image, and then updates it e.g. by resorting or by animating. So that my fingers are in a race with the machine's update. So when I click/tap on what I wanted, it has suddenly changed to something else, a split second before.

How can people do this?

I really just do not get it.