Nothing merely "happens" any more: every occurrence is now an "event", which leaps up and down pointing excitedly at itself. Once, the end of a school term would be marked with a shabby disco down the village hall; you'd turn up wearing the one pair of jeans you owned and circumnavigate the dancefloor nodding your head to the sound of Wake Me Up Before You Go-Go. Now, in 2011, teenagers don outfits chosen by their personal stylist weeks in advance and arrive at their school "prom" in a stretch Hummer. Come, friendly asteroids, and fall on Earth.

Christmas adverts are the retail industry's end-of-term disco, and they have undergone a similar transformation. Not so long ago they were bald sales pitches with a bit of tinsel Sellotaped to the edges. Now the law dictates that any high street chain worth its salt has to bombard the populace with some unctuous cross between a feelgood movie and a Children in Need special.

Take the John Lewis commercial. I heard it coming before I saw it: reports reached me of people blubbing in front of their televisions, so moved were they by this simple tale of a fictional boy counting the hours until he can give his parents a gift for Christmas. Given the fuss they were making, the tears they shed, you'd think they were watching footage of shoeless orphans being kicked face-first into a propeller. But no. They were looking at an advert for a shop.

Failing to cry at an advert for a shop does not make me cold, incidentally. I have cried at films from ET to Waltz with Bashir, at news coverage of disasters, at sad songs, and at the final paragraph of Graham Greene's The End of the Affair. I cried at these things because they were heartbreaking. And because none of them was an advert for a shop.

An advert for a shop. That's all the John Lewis thing is, and as such it's no more moving than the "So Near, So Spar" campaign of the mid-1980s. Anyone who cries at this creepy bullshit is literally sobbing IQ points out of their body. Is this really what we've become – a species that weeps at adverts for shops? A commercial has only made me feel genuinely sad on one occasion – 25 January 1990, when a falling billboard nearly killed 'Allo 'Allo star Gorden Kaye.

Fortunately Kaye recovered. Unlike the family dog in that advert. Yes, it's clear to me that the box at the end of the John Lewis ad actually contains the severed head of the family dog, and that this advert is actually a chillingly accurate short film about the yuletide awakening of a psychopath-in-training. In July the dog was butchered with a breadknife: the deranged young assailant has been waiting since then to present his "trophy" to his parents. Those are the facts. And anyone who thinks I'm lying, bear this in mind: I have asked John Lewis directly (over Twitter) to confirm or deny whether there's a dog's head in that box, and so far it has maintained a stony silence on the issue. Which speaks for itself. So don't sob for the syrupy Christmas story – sob for the slaughtered hound, you selfish and terrible idiots.

Anyway, while John Lewis thinks it's just ace to depict a boy celebrating the sacrificial murder of a dog for Christmas, it has been outdone by Littlewoods, which has annihilated the entire concept of Santa with its offering. For generations, parents have pretended Father Christmas supplies their offspring's gifts: now Littlewoods trains a choir of kiddywinks to warble about how Mum buys all the presents with her credit card. Yeah, fuck off Santa: you're dead to us.

The rest of the lyrics are worse still. It's a terribly sad song. So sad Leonard Cohen should be singing it. "Mum" appears to have purchased an entire nervous breakdown's worth of cold branded goods in a pathetic bid to win the affections of her own family. Her desperate offerings include a top-of-the-range MacBook for Grandad, "an HTC for Uncle Ken", a "Fuji camera for Jen", and a "D&G" for Dad. In case you're wondering what a "D&G" is, the advert makes clear it's a truly disgusting designer watch even Jordan might balk at. In the mad Littlewoods universe "Dad" seems inexplicably delighted by the sudden appearance of this ghastly bling tumour on his wrist, instead of screaming and trying to kill it with a shoe, like any sensible human would.

Worrying in a different sense is the Morrisons Christmas ad, which depicts Freddie Flintoff, whoever he is, building a supermarket and claiming that when they see the range of goods he's got on offer "people will come – people will definitely come". That's an alarmingly low sexual threshold right there. I've been impressed by an aubergine in Morrisons, but not once have I felt like coming.

Marks & Spencer has excreted a mini-musical starring The X Factor finalists, which has to be hurriedly edited and re-edited every 10 minutes, as they keep getting dropped or reinstated courtesy of some scandal or gimmick. It seems a bit low-rent for M&S. If it really wanted to run with someone who'd been in the papers a lot, it would have had more success having its campaign fronted by the bloodied corpse of Muammar Gaddafi.

Perhaps most terrifying of all, after all the above, the Iceland commercial starring Stacey Solomon seems downright reasonable. She's driving home for Christmas and she's so excited she can't stop singing about it. And when she gets home, she's going to inhale a load of suspect vol-au-vents. But so what? It's Christmas.