As in, is it often a projection of how stressed they are at work, and it now shows in their car?
I am from originally from Melbourne, so the drivers there are generally more lay back and while it congested during peak hours, I generally get the feeling that they're not that stressed.
But that's as I was able to compare Melbourne drivers to those in Sydney, Singapore, and other cities in the world.
In that Melbourne drivers give way to pedestrians and it's by law to do so. So if you're crossing the road and a car doesn't stop you're yelling at the driver for not stopping or slowing down so you can feel safe crossing the road. Whereas in Sydney, and if you're a pedestrian, you're the one getting yelled or honked at and needing to get off the road fast.
Singapore is even scarer I have found at times. Maybe I have a bias view, and have only seen a few years worth of drivers, but I was surprised, coming from Melbourne to see a pedestrian crossing the road. I was walking behind them and as they were about half way across the road, they saw a car coming and rather than complete their journey across the road, instead walk (run I should say) back towards me and let the car go past. Now that's particularly surprising to me as it felt like the driver could not care less about pedestrians.
I had another similar experience near an ambulance treating an injured person, and you think it'll be safe to cross the road so close to an ambulance but I was almost run over by a car who pretty much sped and took a took a turn right into the street I was about to cross. Phew wee. It was certainty a close call. They didn't even look like they looked, only if there was another car (that could hurt them I assume) in their way...
Anyway, to the core topic of discussion, both Singapore and Sydney are highly stressed cities, where people work long hours, late nights (and even weekends - Saturdays for most Singaporean companies). In Melbourne, you work during business hours and then head off home at 5 or 6pm, that's it. Normally not working any longer unless you're in industries such as Accounting or Finance. So I can see why Singaporeans and Sydney-siders rush off to reclaim their personal lives.
This contrast between the city of Melbourne and Sydney/ Singapore gives me the impression that driving is an illustration and signifies how stressed and hard people work.
Reader note: I have never worked in Sydney, only in Melbourne and Singapore.