Rudd follows the career path blazed by the likes of the Beach Boys' Brian Wilson, who retired to the chauffeur's quarters of his mansion, beefed up to 147kg and became addicted to booze, drugs and girly magazines. He got so spaced out he could play the piano while asleep.
Or Axl Rose of Guns N' Roses, who became an adherent of past life regression theory, justifying his obnoxious behaviour towards various people on the grounds they'd killed his children in a past life. A girlfriend compared living with Rose to "putting a nuclear warhead in your living room, hitting it with a hammer and just waiting".
Or the daddy of them all, legendary producer Phil Spector, who had a habit of pulling a gun on female visitors to his mansion who dared to suggest that perhaps it was time to call it a night. He eventually pulled the trigger and is now doing 19 years to life for second-degree murder. (Incidentally, if you think Rudd looks a little worse for wear, Google Spector's arrest mugshot.)
While it may be a stretch to call these New Zealand stories, we can take ownership of the one about the Prime Minister who pulled a waitress' ponytail until told to cease and desist.
What are the precedents for this sort of behaviour from a political leader? There's Silvio Berlusconi but he's - how can I put this? - Italian, and never seemed to take the running the country component of his job description all that seriously. He gave the impression he went into politics because he believed - correctly - that he could buy his way into power and assumed - mistakenly - that being Prime Minister was the ultimate stay-out-of-jail card.
Then there's US Vice-president Joe Biden, who raised eyebrows earlier this year by putting his hands on a woman's shoulders and whispering in her ear while her husband was being sworn in as Secretary of Defence.
It turned out Biden was a serial offender: New York magazine detailed eight other occasions when he'd "creepily whispered in women's ears".
But these women pretended they didn't mind, were mostly powerful figures in their own right - Hillary Clinton, the Presidents of Brazil and Ireland - and the creepiness took place in front of large media gatherings, so he couldn't really be accused of behaving furtively or exploitatively.
Perhaps Biden, who is 72, was simply intent on validating the adage that there's no fool like an old fool.
So what are we to make of our Prime Minister who insists he was just "horsing around" but who has been accused of crass sexism and undermining the Gallipoli commemorations? The National Council of Women put out a statement joining the dots between hair-pulling and "our shocking levels of violence against women".
While most Kiwis probably feel that's a bridge too far, there's no doubt that Key has provided us with an unflattering glimpse of himself.
Another customer of the cafe in question admitted to being impressed by Key's leadership following the 2008 global financial crisis but profoundly unimpressed by his hair-pulling antics. Well, madam, it seems you - and the rest of us - got a package deal. We can't have one without the other.