I’ve never been a fan of the phrase “jumped the shark”. Not because I think it’s overused – although I definitely think it is – but I find the premise a bit stupid.

In brief, it comes from the 1977 Happy Days episode when a water-skiing Fonzie jumped over a shark. It was, apparently, the moment the show stopped being good.

The phrase is more than just a comment on quality though. The Fonzie/shark thing, apparently, was when Happy Days stopped being true to itself.

It’s here where my irritation with the concept lies: who gets to decide what a show’s truth is? What the show’s intended vision was?

So I was thinking about this shark-jumping business while watching Series 5 of Californication. I’ve long loved the protagonist, Hank (David Duchovny), based on my unwavering fondness for men who are drowning in problems rooted in women, substances of addiction and art.

QF9 Melbourne to London offered both time and splendid guiltlessness for me to down the season in its entirety.

Akin to how I judge Australian films, I’m a little less harsh on anything watched at 30,000 feet. If it’s less boring than playing another game of Tetris then I’ll consider it decent. That I was fetishising falling bricks throughout the 12 episodes is a pretty damning indictment.

So what was going on? Why, after so many years, was I suddenly finding Hank so cringe-worthy? Why were Karen (Natascha McElhone) and Becca (Madeleine Martin) so gratingly insipid? Why were there so many irrelevant blow-jobs and so many bloody bare breasts?

Which made me ponder the shark theory. To consider whether Californication has “jumped the shark” we need to ask if it’s deviated from the original vision. Is it still the show it was intended to be?

The pilot opened with Hank fantasizing about sex with a nun. It was steamy enough to arouse Andrew Bolt – which illustrated just how terrific it was.

That pilot established that the show was to be about a frequently-sozzled writer finding himself through sex. Come Season 5, therefore, it’s as true – as same – as it ever was.

So if it’s still the same show, if Hank is still fucking and fleeing and Charlie (Evan Handler) is still masturbating and Marcy (Pamela Adlon) is still being fabulously vulgar in a way that only Susie from Curb Your Enthusiasm gets to be – if, evidently, no sharks were jumped – then why was I so devastated that the final sex scene doesn’t in fact kill Hank as I’d hoped? And why does the show feel so horribly hollow?

Is it about comparison?

I’ve written about it in this space before and maybe comparison partly explains it: I started my flight by watching The Sound of My Voice (2011) which was great and which set the bar pretty high. But I’m discerning enough to realise it’d be an apples and oranges comparison.

What about arc-less-ness?

If audiences are offered a character as troubled as Hank, there’ll be expectations – in varying degrees of fervour – that he transforms. Some will want him to get worse; romantics like me will want him to straighten up and fly right back to Karen.

The problem is that Hank hasn’t changed. Not even a little. He might sway – a little more sober one day, a little more drunk and depraved the next – but he’s the same person. And maybe that’s real life – the leopard, the cad, don’t often change their spots – but such stagnancy is rarely sustaining in fiction. Certainly not over five seasons.

How about Fatigue?

A couple of years ago I proposed that Victorians voted out the Brumby government not because they were pro-Baillieu, nor even that they were all that anti-Brumby but just that they were bored; that change was desirable simply because it’s something else. Not only has Hank not developed as a character, but my boredom came from doing the calculations and realising I could have been watching something – anything – that I hadn’t seen before. I wasn’t necessarily after better, just different.

Season 6 starts in January. Yes, I’m a masochist enough to eventually watch it.