Forget politics. Or religion. Same-sex marriage? Nuh-uh.
The best way to ensure some robust debate between friends (especially those interstate or international) is to claim ownership of a certain foodstuff.
Don't believe us?
Take the Neenish Tart.
Essays have been written about the origins of the humble staple of country bakeries nationwide and still, the matter is not settled.
Indeed, the Sydney Morning Herald's famed Column 8 has devoted column inches to the contentious matter in a highly entertaining debate between readers over the years.
Some believe the tasty pastry came from the kitchens of one Ruby Neenish, of Grong Grong, NSW.
Others believe that story, and Mrs Neenish herself, are a fiction.
The earliest recorded recipe of the bi-coloured bite can be found in Miss Drake's Home Cookery, written by Lucy Drake, published in 1929 in Glenferrie, Victoria.
The CWA, for their part, have laid strong claim to the tart, those of German and Austrian descent proffer their own links but we must assume, its true birthplace might never be known.
A Giant Neenish Tart? Controversial.
So in the sweet spirit of taking a bite out of each other, we bring you our top seven foods claimed to be all-Australian - both contested and confirmed in their beginnings.
The Chiko Roll
The Aussie classic (that, in fact, contains no chicken) was invented by Frank McEncroe, born in Castlemaine but later a boilermaker from Bendigo, Victoria - both towns claim him as a favoured son.
In 1950, McEncroe saw a competitor selling Chinese chop suey rolls outside Richmond Cricket Ground and hit upon the idea of a substantial snack that could be held in one hand leaving the other free for more important business at the footy - opening a cold one, for instance.
The Chiko Roll, debuted at the Wagga Wagga Agriculture Show in 1951 but made a triumphant return to the southern state in 1960s, McEncroe moved to Melbourne with his family and began to manufacture the rolls en masse.
The Meat Pie
Woah Nelly! The meat pie an Australian invention? Many, many countries lay claim to the mighty meat pie, firstly by Ancient Egyptians (9500 BC), Greeks, Romans, the English, Latin Americans and on and on and on.
But, you'd be inviting trouble if you denied Australia fair bragging rights in the invention of the snack in its current form.
One of the most famous was first produced in 1947 by L. T. McClure in a small bakery in Bendigo and was destined to become the famous Four'N'Twenty.
Older still, Sargents Pies can trace their pie making back to 1906, but George, Charlotte and Foster Sargent - before they lit out on their own - had already been selling pies for a penny in a small shop in Paddington, Sydney since 1891.
In South Australia, Balfours and Vili's have both been making pies for more than 100 years.
Which brings us to…
The Pie Floater
The pie floater - an upside-down pie in a bowl of pea soup, topped with either tomato sauce or, sometimes, Worcestershire Sauce (controversial, we know) - was reputedly invented by a South Australian Port Pirie baker known as Ern 'Shorty' Bradley at the turn of the 20th century. Woolloomooloo's Harry Cafe De Wheels deserves an honourable mention for having served the, uh, attractive dish since it opened its shutters in 1938.
Most of the argy-bargy surrounding the origins of the Lamington concern the name - while most agree it was named after Lord Lamington, who served as Governor of Queensland from 1896 to 1901, although some reckon it was for his wife, Lady Lamington. Another account reckons they were named after the Scottish village of Lamington, South Lanarkshire, however this may be pure semantics as the Lord hailed from Lamington and now we are splitting coconut flakes…
It is mostly accepted the treats were first served in Toowoomba in 1900 when Lord Lamington took his entourage to Harlaxton House to escape the heat of Brisbane.
The Dim Sim
Invented right here in Melbourne by Chinese chef William Wing Young for his restaurant Wing Lee around 1945.
But the mighty meaty dim sim really got its cult following at the South Melbourne Markets sold by Melbourne legend Ken (Kuen) Cheng from 1949 until his death in 2006. Vale.
The Iced Vovo
Kevin Rudd poured a giant cup of cold tea on the Labor Party faithful's celebrations at being returned to power after 11 years in the wilderness in 2007 by suggesting everyone calm down and have an Iced Vovo.
But a greater shock to the system is that the iconic jammy biscuit isn't actually ours.
Or so those dastardly New Zealand types would have us believe. Apparently a Kiwi biscuit company going by the name Auselbrooks, established in the 1860s, were making Iced VoVos well before Arnotts registered the name.
And Arnotts have quietly acknowledged this to be true.
Humph. Enough to make one take a Bex and have a good lie down.
Ah. The great bone of contention between Australians and our Kiwi cousins.
So the story goes like this. (The real story. Promise).
Inspired by visits by the Russian ballerina Anna Pavlova during her 1926 and 1929 tours of Australia, Western Australian chef Herbert Sachse of Perth's Hotel Esplanade created a confection that was "as light" as the prima ballerina herself. End of story.
Except, these origins are heavily disputed by New Zealanders who claim their cookbooks have older versions of the fruity, creamy, light, delicious summer dessert.
Anyway, you can always complement your meal - pie floater, meat pie, Pavlova, anyone? - with a glass or two of "plonk".
It's a term that came from Australian soldiers on the Western Front in France during World War I.
To their untutored ears, vin blanc - white wine - sounded like "plonk".
They adopted it as their word for all forms of wine, and brought it home, where it stayed. So it's a well-travelled term.
And it's ours.