I happened to be in Canberra last Friday, speaking to a room full of journalists at the National Press Club, when the news came in — halfway through lunch — that Australia had a new prime minister.
The moderator pointed out that the year is already two-thirds gone and it is "only three prime ministers till Christmas", while the China Daily's headline read: "Australia changes its prime minister again, again, again, again, again."
The new prime minister, Scott Morrison, is the third leader of the governing Liberal (i.e. conservative) Party since 2015. In the five years before that, there were three prime ministers from the Labor Party.
Only twice were those prime ministers chosen by the voters; in the other four cases, the changes were driven by intra-party coups – "spills", in the Australian political vernacular.
Mockery is appropriate, and it was not in short supply when Prime Minister Malcolm Turnbull was overthrown by his own party last week.
"In the future everyone will be Australian prime minister for fifteen minutes," tweeted 'Not Andy Warhol'.
Another online commentator pointed out that "Game of Thrones is not an instructional manual."
But it is, in Australia. Back-stabbing is old hat; the new fashion in both major Australian political parties is "front-stabbing".
Yet there are no great issues at stake, no national crisis that must be overcome.
Australia is still the 'lucky country' — 25 million people with a healthy economy (they didn't even have a recession after 2008), no enemies, and a whole continent to play with.
What drove the latest spill was a challenge to the sitting prime minister by Peter Dutton, an MP from his own party.
Dutton is on the Liberal Party's right wing and didn't like Turnbull's relatively enlightened climate change policies – but even when Turnbull dropped his new emission control proposals the revolt continued.
And in the end, although Turnbull went down, Dutton did not take his place. Scott Morrison, a man much more in Turnbull's mould, did.
To outsiders it seemed utterly pointless, a not very large tempest in a teapot, but it transfixed the Australian media and paralysed the government for several weeks.
So what is causing this weird behaviour in an otherwise fairly sensible country?
Is it just a passing lunacy like the "dancing mania" of the late Middle Ages in Europe (which was never adequately explained) or the hula-hoop craze in America in the late 1950s? And, more importantly, is it a communicable disease?
Australian politics wasn't always like this. Between 1983 and 2007 Australia had just three prime ministers.
Elections (in which everyone must vote or pay a $20 fine) happen every three years or less, which is clearly too often, but the political system was the same back when Australian politics was far more stable.
The fact that Australian politicians are never more than three years away from the next election certainly encourages a short-term perspective, but it doesn't explain why they are always changing horses.
Maybe you have to add to the mix constant opinion polling and a 24-hour media cycle that demands some new political news every day. The opinion polls are read as a judgment on the party leader's ability to win the next election.
When Malcolm Turnbull ousted former Liberal prime minister Tony Abbott in 2015, he said: "We have lost 30 Newspolls in a row. It is clear that the people have made up their mind about Mr Abbott's leadership."
And out Abbott went.
So when Turnbull lost in 30 consecutive opinion polls (they come out about every two weeks), he too became vulnerable – and the Australian news media, always looking for the next big story, began stirring the brew.
The Liberal Party's MPs panicked (again) and since the most obvious way they could try to change the predicted outcome was to change their leader, that's what they did.
But other countries have opinion polls and hyperactive media too, and their parliaments don't act like that.
They may benefit from the fact that their elections are less frequent (every five years for parliamentary elections in Canada, Britain and France), but they don't act like that even in the last year before an election.
The conclusion is unavoidable — this is an essentially random and purely local case of "monkey see, monkey do", like "dancing mania" and hula hoops.
Julia Gillard organised a revolt against the Labor Party leader and sitting prime minister Kevin Rudd in 2010, he returned the favour and overthrew her just before the next election, and the game was on.
Rudd lost the 2013 election and the last three prime ministers have been Liberal, not Labor, so the infection can clearly cross party boundaries.
Since there is an election due next year, which the polls predict Labor will win, there will probably soon be yet another Australian prime minister.
But there is no sign, as yet, that the madness can cross the oceans.
Gwynne Dyer's new book is "Growing Pains: The Future of Democracy (and Work)"