I think there is a sure fire litmus test that can be used to determine who grew up in Australia and who didn't. Vegemite.
Around the corner from my new work is a cafe we (rather literally) call "The Russians" because, amusingly and with a complete lack of irony, it is run by a trio of Russian women. Lately one of them has been away on leave, and so there is a young English guy helping out with the morning shift. (I'm pretty sure he's the cook's boyfriend, because there is a series of photos posted up on the wall called "Staff Meeting" and aside from some pictures of the Russian women drunkenly dirty dancing with the pair of them, there are at least two pics of the two guys cuddling.)
Anyhoo, this morning I ordered a coffee from the new guy and (for a change) two pieces of wholemeal toast with Vegemite. He failed the litmus test. When it arrived there was a layer of Vegemite that can only be described as overly generous. You see the big test is the amount of Vegemite. The thinnest of thin smears is perfect, a half centimetre thick layer is not. Eat that and you're courting salt overload and a mouth full of dead tastebuds.
Shortly after delivering the plate to my table, another customer walked past and took one look at my plate and said "Gee, like Vegemite?". Indeed. So I grabbed a knife, scraped off 90% of it, and it was still really strong. When he collected the plate and looked at the huge mound of discarded Vegemite (think Richard Dreyfuss, mashed potato and "Close Encounters of the Third Kind") he gave me a sheepish look and a smile that said "Oops". Definately not from around these parts.