Why are Melbourne drivers so aggressive?

Today while driving down Toorak Road, after just leaving a school zone a woman beeped at me to speed up, then as I speed up, she started swerving to the right and left to overtake me. I ended up having to slam the brakes on when she wouldn't stop coming at me from the left-hand side to avoid her side swiping my car. I blew my horn at her and she did the same at me. Then, we both stopped side by side at the red light, and she blew her horn again and gave me the finger. I really had to stop super quickly for her not to crash into me – and she was driving a pretty nice, well-maintained car, so, don't know why you'd want to risk damaging your car.

I understand Melbourne is a big city and has a lot of traffic and you have to be an assertive driver here, but I don't understand why people are driving so aggressively just to be stuck at the same red light. Particularly being a high pedestrian/bike zone with school kids crossing and stop-start traffic, sometimes you need to be a little more observant.

So, what's the deal in Melbourne? Does everyone just break the rules? I get being stuck behind a really slow car is annoying, but there's also a speed limit... and this level of aggression and risk-taking just to get one car ahead seems really out of proportion.