I've read Downunder and At Home, but it's been a while since I read the former.
Us Aussies are generally laid back and have a tendency to not take ourselves too seriously. For instance, among males the words "old bastard" are usually a term of affection. And we do like poking fun at authority. We are only human, and it is nice to be reminded of that remind others of that.
We aren't very political, our last election had vote counting that lasted about a week and the prevailing attitude was "get on with it".
Boxing Day is when a lot of Aussie males, and some females, go into a cricket induced coma with the Boxing Day test. And we always win, even when we don't.
We don't have a lot of wedding traditions, they follow US and UK a bit but with a bit more of a laid back approach. It's perfectly fine to include registry info with an invite, just ON the invite is a bit too much. The couple will pay for it themselves, with sometimes contributions from family and friends. Who pays for BM dresses can go either way or halfway in our case, as long as you are upfront about it.
And we do have more public holidays here. Easter is typically a four day weekend.