Rush hour on a particularly heavily congested road, a driver looking for an address unknowingly cuts off another driver on his way to work. The second driver angrily pressed on the horn as he passed the first driver and proceeds to give him "the finger". The second driver acknowledged his mistake and quickly flashed "a peace sign". The first driver accepts the apologetic gesture and waves as he drove off to work.
Hand gestures are universal means of non-verbal communication. Its values can range from very cordial greetings to aggressive and sometimes even offensive acts. This simple diagram is meant to illustrate the very small difference between two extremely opposed universally accepted hand gestures.