NSW - New South Wales
SA - South Australia
I lived in Sydney (honestly, 60km from my place to Sydney) for roughly three years. At the moment, I am living and studying in Adelaide, South Australia. Australia is a big continent with multi-cultural backgrounds. After living here for more than three months, I am not too confident to say that I clearly understand about people living in Adelaide. However, I have recognised some slight different between here and Sydney (based on the surroundings around me).

P.s: The discussion below is based on my personal viewing lens. I acknowledge and respect other critics and more than happy to listen from all of the readers.

Overall

Similar to Vietnam, there are crowded and busy cities and also quite areas. I reckon that Sydney is like Ho Chi Minh City in Vietnam and Adelaide is more likely to be Can Tho City.
Sydney is always busy. It is a young and dynamic city. People living in Sydney have fast-paced living style. Simultaneously, Adelaide is a laid-back city which has everything. However, Adelaidian tends to relax and enjoy life.

Social focus

Based on my limited knowledge (specified in Social work-study), Social work - study's structure and State's legislation are pretty different from state to state in Oz. SA's primary focuses are on children and old people. During the group discussion, my group member raises a question: " Why other states like Vic and NT do not have many policies about children's rights?". I answer that may because of their resources. Similar to human's competitive advantages, different states will have a plethora of issues, but with limited financial and physical resources. Therefore, they only pay attention to one or two set of minority groups.
Specifically, as I just mentioned, SA focuses on aged and the youngest (under 18) population. At the same time, NSW's priority is on people with disabilities. I also notice that Victoria (Melbourne) has the largest number of refugees and homelessness in Aus. As a result, there are lots of agencies and residential support for homelessness in Melbourne.

Language

There are a number of vocabulary that was used here but not in Sydney.

E.g: reckon: ~ think/ suppose
I remember that one of my lecturer (at the University of Wollongong) told me that "reckon" is an ancient word. They didn't use it for ages. Therefore, she felt strange when I used it.
However, lots of staffs and people in Adelaide use it at the moment.