Greens co-leader Metiria Turei nailed it: "New Zealanders know you can't walk into a cafe and start tugging on someone's hair." Kiwis were understandably flabbergasted that their Prime Minister hadn't grasped this obvious truth.
Another factor in the scale of the reaction is that, if you take kids and kittens out of the equation, Key pretty much has hair-pulling to himself. If he'd just been overly familiar, a little too touchy-feely, he probably wouldn't have made himself an international object of ridicule, as in this from John Oliver: "John Key can't pass any piece of dangling hair without pawing at it. He's more cat than Prime Minister."
Thirdly, while the act in and of itself may be relatively innocuous, it symbolises something bigger. For many women, the Prime Minister taking liberties with a comparative stranger's hair is a reminder of the low-grade indignities to which they're continually subjected: invasions of personal space; uninvited hands lingering on the small of the back; roaming eyes and suggestive eye contact; flirtatiousness in inappropriate settings.
At the political level, Key's behaviour reinforces the perceptions of those who've never liked him or always had misgivings about him: that he's a crowd-pleasing lightweight who lacks the gravitas required for high office.
And it's simple, and simple stories capture and hold the imagination: boy meets girl; hero saves the world; Prime Minister pulls ponytail.
To the endless frustration of the serious-minded, the public is rarely riveted by dense policy debates or complex narratives even though they may be vitally important or lead to a scandalous conclusion.
Republicans are attempting to derail Hillary Clinton's presidential campaign by uncovering a scandal at the Clinton Foundation, a charitable organisation that employs her and husband Bill's star power to suck in money from around the world which is put to various good uses. There are suggestions of financial impropriety and influence peddling with regard to foreign, and not necessarily admirable, governments.
Unless they're sitting on a video of Hillary frolicking naked with Vladimir Putin in a swimming pool full of vintage champagne, I'm not sure there's much mileage in this. It's too abstract and impersonal.
The Republicans should know this better than anyone. In the 1990s they fixated on the Whitewater scandal that was supposedly going to expose the Clintons as crooks, if not parties to conspiracy to commit murder. Investigations and hearings dragged on for years at vast expense and achieved precisely nothing.
Yet the Monica Lewinsky scandal, Bill's brief, tawdry liaison with a White House intern, led to impeachment proceedings.
While Clinton escaped impeachment, the lingering scandal made the Democrats reluctant to use their greatest asset in the cliff-hanger 2000 presidential election which his Vice-President, Al Gore, lost to George W. Bush. And we know what happened next.
As Benjamin Franklin, one of America's founding fathers, pointed out: "A little neglect may breed great mischief."
