Get off your high horse, perfectly reasonably manoeuvre, do something useful with your life rather than constantly looking out for other people's mistakes. Read a book, do something get a life
This car did exactly the same thing to me outside Reading on the M4 and did it to other cars before taking off. We were overtaking a middle lane hog and he undertook on the inside lane then he pulled violently in front of us (there was 2 car lengths between us and the car in front), tried to intimidate the driver in front by sitting on their bumper. When we came up to a lorry overtaking another lorry he dangerously undertook the lorry in the middle lane who had to brake when this car pulled in front of him. the guy is loopy!
Silver 2013 Mercedes-benz Ml350 Amg Sport
What a total idiot!