As an Englishman who's known many Aussies in my life I've found there is one sure fire way to get into a heated debate with them.
You don't need to mention the rugby.
You don't even need to mention the cricket.
All you need to say is: "Marmite is better than Vegemite". Next thing you know, they're Tim Cahill and you're the corner flag.
Happy birthday to me.