I've found that the Merc drivers are worse!  ...  Mercs are the new BMW drivers : )  
  
Reminds me of an incident that happened to myself.  I once pulled out on two lane dual carriage to overtake a car and a bus decided to try and use some form of drafting technique, I had pulled out in plenty of time as well.  Next thing he starts flashing the lights ... enter rage mode for me.  I proceed to overtake the car as originally planned, knowing we we're approaching the mother of all hills.... then at foot of hill drop 3 gears and leave the bus to crawl up the hill .... hahahaha  Car 1 - Bus 0