first cut them off then flip them off

The phrase is used as advice for impatient drivers (usually impatient, incompetant yuppy sorts in overly expensive cars) who hesitate when a much slower car approaches the intersection (usually driven by an old fart with a handicapped sign on the mirror). If the yuppy waits, he will inevitably be trapped behind the slow old fart for a long time. Thus the advice, "first cut them off, then flip them off" intended to not only offend the other driver by cutting them off, but also to infuriate them by giving them "the bird" immediately thereafter. A totally un-called-for move which is very hilarious, it is also summed up by the phrase, "those who hesitate, wait". Either phrase perhaps best summarizes the attitude of extreme, offensive driving- skills not taught in your average Driver's Ed Class.