Please pay close attention to the video below.
When you stop all the traffic behind you to let someone in who clearly doesn't have the right-of-way, or when you just aren't paying attention to traffic flow, your actions create shockwaves behind you. The drivers that follow must pay the price for your actions quite a while after your "good deed" is done.
This video is a lab experiment demonstrating the effects of human error and how it creates shockwave traffic jams.
22 cars were to drive around the circle at 20 miles per hour. Ideally, each car would maintain an equal distance to the car in front of them and should have no reason to compromise that space. UNTIL SOMEONE SCREWS UP.
Click to view
The moral of the story is: QUIT BEING A DUMB-ASS DO-GOODER, PAY ATTENTION AND JUST DRIVE! argh!