When you are trying to turn left into a slip lane and the driver in front doesn't notice and doesn't maneuver their car in the lane to allow cars behind them through.
Or right, for that matter.
You don't need three metres between you and the car in front of you, you selfish cock!
People who fill up a roundabout preventing cars entering from the side. It's illegal, you know.
Similarly my office car park leads out into a busy arterial road through a traffic light. Cars are totally happy to fill up the intersection - stationary - so only a car or two can exit per 15 or 20 second green light cycle for exiting cars. This stops those cars getting behind a handful of us, and makes us wait minutes to the next cycle. It's (almost unbelievably) a rare car that hangs back and leaves any room at all.
And tailgating. I think Melbourne's drivers are among the world's most selfish.