There was a time when everyone knew their neighbours intimately, popped around often for a cup of tea and a gossip, collected your mail and fed your dog when you went away. India and Sri Lanka seemed about that close when they met in the 2011 World Cup final; in the previous five years they had tossed the coin in 39 ODIs against each other. They were co-hosts in name and nature.
Australia and New Zealand have slipped into the modern neighbourly way, nodding politely when they happen to run into each other on the street, but never visiting each other's house. In the past five years they have met in not a single ODI outside of ICC events. It hasn't always been that way: in the previous five years they played 23 such one-dayers against each other.
They have drifted apart, Australia more interested in the big-ticket campaigns against India, England and South Africa. But then, it had always felt like New Zealand prized the Chappell-Hadlee Trophy far more than Australia. In 2006-07, Australia didn't even bother sending their captain or vice-captain to the series in New Zealand, and Michael Hussey led them to defeat.
Of course, there is nothing new about such goings on - or non-goings on. Australia did not deign to play a full Test series against New Zealand until 1974, a full 44 years after New Zealand were admitted to Test cricket. The underarm incident and the might of Richard Hadlee sparked a 1980s rivalry, but it is now a decade since the teams have played a Test series of more than two games.
In the eyes of the Australians, the rivalry has died off. When the teams met in the Champions Trophy in England in 2013, they forgot to put the Chappell-Hadlee Trophy up for grabs as they had done when they played in the 2011 World Cup. It was dusted off for their World Cup meeting in Auckland this year, and New Zealand won a low-scoring thriller.
And yet, when New Zealand arrive later this year for Tests in Australia, they will use a pink ball and play day-night cricket, and will not be granted the Boxing Day Test at the MCG. No extra motivation is required for a World Cup final, but if New Zealand need it they have it. On Sunday they can prove they belong in front of a packed MCG.
"We're probably seen as the little brothers from across the ditch and we do quite well in other sports to compete," New Zealand fast bowler Tim Southee said on Friday. "Australia have had the wood on us in cricket over the last few years but we're slowly starting to even that ledger.
"As a kid growing up it was always Australia that you wanted to play against, or if you're playing against someone in the backyard it was New Zealand-Australia. There is a massive rivalry in whatever sport you play and in New Zealand you always want to have one up over the big brothers."
Ask an Australian cricketer what featured in their backyard games when they were kids and it would likely have been an Ashes imitation, or Australia against the golden era West Indies. The 11 Australians who will take the field on Sunday have probably dreamt about playing in a World Cup final, but against someone like India, or South Africa.
New Zealand, with its near identical flag, its non-Australian-passport-stamping ways, its population smaller than Sydney - it has hardly been viewed as a big threat by Australia's cricketers. In rugby union, yes. In netball, sometimes. But not in cricket. They should remember that New Zealand won the most recent Test between the teams, and the most recent ODI, and the most recent T20 (in a Super Over).
"I think in times gone by we probably haven't played to our potential or been as consistent as we should have been," Southee said. "In the last two years we've slowly gained a little bit more respect around the world because of the brand of cricket we've played. We respect Australia.
"They're a quality side, they're not No.1 in the world for no reason. I'm sure they've gained a little bit of respect for the brand of cricket we've played over the last couple of years. I guess that opinion has changed a little bit over the last couple of years in the way that we've played and the sides we've beaten."
Sides like, say, Australia, when given the chance. Beating Australia in a World Cup final would be the ultimate respect-earner. On Friday, the Cricket Australia chief executive James Sutherland said that the co-hosts had "dared to dream" that they might meet each other in the final.
"We knew it was probably a long-odds chance, but here we are a couple of days out and the two host nations are playing each other," Sutherland said. "Congratulations to New Zealand on making the World Cup final. They've been unbeaten throughout the tournament and are certainly deserving of playing off."
Sutherland's tone was not patronising, though seeing the words in black and white they might look that way. Viewing the Australia-New Zealand fixture list of the past five years they probably appear even more so. The World Cup final might change that.
Perhaps Cricket Australia should remember what all Australian TV soapie fans know: everybody needs good neighbours. Neighbours need to get to know each other. And next door is only a footstep away.