Anyone who has done user testing will tell you that the click-click-click-smash-smash-smash of frustration is both the sign of a design problem and a QA bug hunt waiting to happen.
An inquisitive Kai took the problem and went one stop further, asking StackExchange Why do users click randomly and rapidly when an application hangs?
Some savvy StackExchange users provided some great responses, including Mervin's succinct analysis featuring the history of keys themselves. Dylan Meador went down the biological route and dug out some quotes about Extinction Burst.
StackExchange, you win again.