Some say that the once-strong Anzac bonds are unravelling, with Kiwis seeing Australians as crass, racist and sexist and Aussies seeing their Tasman neighbours as dominated by a culture of pessimism, self-doubt and reserve. One area of mutual disquiet, though, is Asian immigration.
Australian Gabrielle Zerafa well remembers her first mouthful of New Zealand yoghurt - she gagged and nearly spat out the offending dairy product.
Perhaps it was a mistake, she had bought the wrong product? No chance, this was a pottle of yoghurt, New Zealand-style, and entirely different from the fermented milk sold across the ditch.
It was at this moment that the head of Colmar Brunton NZ's qualitative research department realised she was living in a foreign land, not some cosy transtasman extension of the lucky country.
For the fair dinkum Australian boss of the Warriors, Mick Watson, the epiphany of alienation came at his son's first soccer match - these bloody Kiwis were playing for fun, with no winners or losers.
His sense of outrage at this sporting travesty is palpable, but he has subsequently reconciled himself to the fact that New Zealanders do things a lot differently.
For widely known New Zealand journalist and now Sydneysider Spiro Zavos, the same moment arrived at a press conference for Roy Jenkins, the Chancellor of the Exchequer in the Harold Wilson government, a story he was covering for the Sydney Morning Herald.
Well-versed in the New Zealand deference afforded officials from the Mother Country, he was shocked at the disrespectful line of questioning from Australian journalists. "[These days] if someone is coming up on rape charges, they're outside asking how it feels to be a rapist, almost ruining the case."
On his first arrival, Wellington businessman David Benge, who runs music company Atlantis Management in Melbourne, was gobsmacked by the overwhelming amount of advertising featuring naked women: "Fundamentally, Australia is a lot more sexist and a lot more racist."
Their reaction to their respective new homes is typical. And it is perhaps shocking that all three men, even Zavos, who has lived in Australia for 25 years, still feel they are living in a foreign country.
"For a New Zealander," says Zavos, "it's a much greater shock, a cultural shock, in every way to live in Australia than it is to live in the UK."
Shared wisdom has it that, despite the differences, there is a collective Anzac spirit that endures to this day. Rugby raconteur and former Wallaby Peter FitzSimons adores New Zealand and is adamant that "the things that unite us are far greater than the things that divide us".
Well, Zerafa has news for him; the old Anzac is dead and buried in a graveyard somewhere outside Monte Cassino.
Or, to put it more baldly, New Zealanders and Australians have nothing in common, a divergence of culture that extends as deep as our sense of taste.
Take the yoghurt. Zerafa says New Zealand dairy is "creamy-sweet", perhaps in some way influenced by Polynesian
preference. Whereas the Australian equivalent favours flavours that reflect the Mediterranean and Vietnamese immigration heritage and is "almost sour", she says.
As a qualitative research scientist, Zerafa is ideally placed to examine the differences. Her work on both sides of the ditch is used by corporates, politicians and sundry organisations to better understand their constituencies, whether to sell wares, policies or ideas.
"I came here actually because the best qualitative research in the world is done in New Zealand, and I've seen research from all around the world and without doubt it's the best," she says. "Everybody says the good qualitative research is done in London, but I don't believe that for a second. Qualitative research is about understanding what motivates people, why we do what we do at a subconscious level and how that all translates to behaviour. It's psychology in its purest form."
Benge's shock at Australian advertising is well-based, she says, talking about an infamous billboard for Bond's holeproof knickers featuring an ample female behind with a wooden ruler strategically placed to stop ride-up.
"Australians think it's hilarious; they think it's crass, but think it's funny. [In New Zealand] they just think it's crass ... and that is a fundamental example.
"On the surface we seem identical, but deep down I think we are fundamentally different.
"Look at brands - what would be considered first tier in Australia is often a second tier brand in New Zealand. Mars bars in Australia, Moro in New Zealand."
Both brands have tried to topple the other "God knows how many times and never succeeded". A lot of New Zealand businesses have failed in Australia, but "a lot of Americans have gone to Oz and then pulled out [too]".
The difficulties of transportation, geography and distribution are complicated by the fact that Australians do business in a different way.
Telecom chief executive Theresa Gattung said as much in a recent speech to the Shareholders' Association, talking of the win-at-all-costs Australian attitude: "We think they are our friendly cousins and they think we are their munty next-door neighbours."
As hard-nosed Australian businessman Watson says, Kiwi corporates are "so European, so Commonwealth-influenced, so conservative", whereas Australians are "very US-focused".
"In Australia, you're allowed to say, 'I've done well, I'm successful and I would like to adjust my lifestyle accordingly.'"
Whereas New Zealand sports stars largely reflect an ethos of self-deprecation, "Australians are moving towards the US, [like tennis star] Lleyton Hewitt, fist pumping towards the crowd."
Understanding the cultural differences, Zerafa says, is as simple as looking at the respective environments and heritage.
"Obviously, Australia started as a penal colony, an English stronghold in the southern hemisphere, but very, very Irish in base population," she says. "New Zealand seems more Scottish in base ... it does have an effect on attitude. With the environment, Australia is a very harsh place to live - extreme temperatures, very little water - whereas New Zealand has an abundance of food and water.
"So, I think that has actually bred a different attitude at the end of the day."
She talks about New Zealanders being "barriered", cautious and reserved - "they tend to doubt themselves".
Which are comments similar to the advice once handed out by an Australian journalist to her Kiwi counterpart that he would get ahead in his trade if only he could stop being so "cringingly diffident".
For instance, in interviews Zerafa struggles to get New Zealanders to talk about logical and rational concepts, her subjects immediately turning the conversation to feelings. Conversely, trying to get Australians to talk about their feelings "is like pulling teeth".
FitzSimons vehemently disagrees: "[Although] I was never in any doubt about Richard Loe's feelings at any given moment ... David Campese's striking sense of logic never made a huge impression on me."
Zerafa says Australians are less concerned with failure. "They get out and do it, figure it out as we go. And if it works, it works, but if it doesn't ... we'll just start again. I don't think it's about confidence, it's a necessity, and you have to go back to the environment of Australia."
Zavos's observations concur with her view. He recounts the difficult start for the colony, which was not self-sufficient until "they found a way through the Blue Mountains. It was typical of the Australians that nobody asked the Aboriginals. They tried [and failed] to do it themselves, [but] they finally found a way through.
"New Zealanders' predominating trait is a sort of pessimism, whereas Australians' dominating trait is optimism. Last year, the Wallabies got beaten by 50 points. [If the result were reversed] it would have destroyed New Zealanders. But they say, 'Oh well, we'll win the next one.'"
Zerafa: "New Zealanders are a lot more intense about their sport, there is a deep mourning that goes with a loss."
Mick Watson is bemused, but loves New Zealand, which he describes as "the last bastion of decency - I think it's all about integrity, fairness and equality".
Some New Zealanders, such as Warriors owner Eric Watson, had a "US-focused Australian mindset" that was about "performance, being number one and winning", he says. But they are the minority.
Issues of race and immigration are other ties that both bind and divide. Zerafa says, "Australia sounds very racist ... but it's not institutionalised racism."
New Zealanders have their doubts on this point, with Benge, whose Melbourne company's roster of artists includes chart-topping Kiwi band Fur Patrol, saying he finds Aussie attitudes racist. He is still aghast at the absence of Aboriginals in Australian life. "You just don't see Aboriginal people in Australian cities," he says. "In New Zealand, you see Maori, but here ... you literally don't see them."
As Zavos notes, a popular slogan during the 60s was "Australia for the white man".
Zerafa says, boatpeople aside, Australia has accepted immigration - "we've had 150 years of immigration" - but the two countries have different approaches.
"In Australia, when immigrants come in, it's very much [about forming] little communities - Greeks, Italians, Vietnamese - and never the twain shall meet," she says. "In New Zealand, that doesn't seem to happen. [But] I think New Zealand is facing its first major test in terms of immigration. New Zealand is at the crossroads; are we in or out of the global economy? And my feeling is this pulling back from everywhere is getting stronger."
In one sense, Australians and New Zealanders are alike - Zerafa says they share a mutual disquiet, which she does not consider racism, over Asian immigration. This has had the unexpected outcome of uniting Pakeha and Maori to face this so-called threat, she says.
Immigration is a deeply unsettling issue, but one that Mick Watson has vehement views about and his comments make uncomfortable reading: "As an Australian living here and with the full intention of staying here, [I say] beware immigration. Just look towards Australia [and what has happened there since] opening the floodgates to South-east Asia. Look at the [problems of] a growing population ... of crime, cultures that refuse to accept your culture."
In Watson's view, Asian immigrants have ruined Sydney and he would hate for Auckland to suffer the same fate.
But then Australia does have a long history of fearing Asians, whether the Yellow Peril or Indonesia. Zerafa says this fear is genuine and still continues to this day, clouding the country's foreign policy and public attitudes. For instance, women were not granted the vote because of any mass Australian sense that women were discriminated against, she says, but rather the decision was based on the pragmatic view that Chinese immigrants and poor people should be denied rights.
"Women got the vote to stop the Chinese and poor people being able to get land and votes in Western Australia. It was considered better to have a white woman vote than a poor, immigrant male - it was the attitude of the time."
Australian attitudes are also based on a strong sense of cultural identity, one that has emerged in the last 15 years. New Zealand, in a sense, is still trying to discover or establish this sense of identity or cultural belonging, despite cutting its apron strings to the Mother Country.
As FitzSimons notes, the republicanism argument is well-defined in his homeland, whereas "I have barely discerned a flicker of debate in New Zealand about that".
If Zerafa's contention about identity confusion is correct, then it is perhaps understandable that Kiwis look across the Tasman, even if only to have an established culture against which to define ourselves. And perhaps it is this that explains New Zealanders' deep sense of hurt that Kiwis don't really register in the Australian consciousness.
Zerafa says there is almost a sense of betrayal among New Zealanders since the 9/11 terrorist attacks. "Australia has taken on the terrorist issue quite seriously, it's obviously formed a relationship with America and that is very different to New Zealand's stance. People talk all the time about [how] Australia is part of America and New Zealanders are very upset by that. There is a perception that Australia has sold out, which is a real shame."
Zavos: "It's a society like America that rewards excess, but is not so good at looking after people who aren't successful, [whereas] we are a decent society."
With Australia looking to the US, New Zealanders believe the countries are drifting apart.
"How far is divergence going to go?" asks Zerafa. "I think we will probably continue to diverge."