One of my favourite quotes from the old series of NRMA radio ads involved the premise that one character had stopped his car at a set of traffic lights and was talking to the driver of another car, even though the light had turned green. The angry motorists behind start to heckle, and one yells out "What are you waiting for – a brighter shade of green?"
It still makes me laugh, though the ad was years ago.
What are you waiting for?