Feeling a bit porky and raddled after your December debauch? Want a new you for the new year? A plastic surgery firm is offering three treatments for the price of two. That's right, have, say, your lower eye-bags removed and your breasts enlarged and they'll throw in a labia reduction (a lucrative new source of self-hate apparently) or a neck lift absolutely free! But hurry — all surgery must be completed before the end of January.

Clinics offering cut-price ops, this week condemned by Which?, encapsulate the utter rubbishness of sales mentality: allowing yourself to be harried into buying something you don't want — and certainly don't need — under the guise of saving money.

In Selfridges on Thursday for my traditional exchange of wrong-sized Christmas sweaters, I watched women in the handbag section snatch up totes and clutches, barely looking at what they were buying. To shop so excitedly so soon after Christmas is to me as nausea-inducing as eating a huge turkey dinner, patting your straining stomach, then stuffing down a deep-pan pizza.

What kind of consumer gluttons have we become that the head of PC World can gloat that his customers prefer to spend Christmas Day shopping online rather than “sitting in front of elderly relatives playing charades”. You've just opened your presents, but why waste time talking to the people who bought them when you could be shovelling up more stuff.

The head of IMRG, the online retail body, is right: “When stores close, the desire to shop doesn't go away.” No, these days, it is unabated. Debt and obesity are products of the same problem: a modern inability to know when we have consumed enough. Appetites distorted, palates jaded, we eat and spend with joyless greed. Witness women at the Primark sale below mountains of Lycra tops that they will barely wear, because there are not enough days left in the fashion season before a whole new list of “must-have” items is decreed.

Shopping is our only common leisure pursuit, the medium through which we experience the world. To shop is to be. Little wonder children are found once more to have rickets: what chance of soaking up vitamin D being dragged every Saturday around sunless malls?

Shoppers: your Government needs you! Keen consumers are valiant footsoldiers in the battle against recession. Reports chide them for cowardice and hesitancy before Christmas. But now, into the high street war zone they charge, hoovering up wares, fearless of the coming credit crisis, or even personal injury, in the case of three women shoppers who almost expired from hypothermia, queuing from 4.30am outside Next.

A million British people are so broke that they're funding their mortgages or rent by credit card, repaying one kind of debt by creating another. The notion of living within one's means is as archaic as rationing. No one saves for anything, never anticipates a pleasure: why wait when you can slap it on the plastic. The gap between a desire and its satiation is fleeting. And so the craving never ends.

But I have never bought anything I truly love in a sale. A good deal on a new washing machine was appreciated when our old one was bust. But how can you care for a dress dragged from a discount bin, in a store like a ransacked shantytown, which was rejected by all who came before you? Once inside the fitting room the colour is draining, the cut unflattering. It is in the sale for a reason. And sales encourage us to ignore an item's intrinsic worthlessness and be seduced by the hokum of designer branding. OK, it's a crop-top purple cowl-neck shroud — but, hey, it's cheap and it's DKNY! Yet one perfect full-price frock gives better value than four bits of tat that never quite fit.

'Tis the season for rows in shops. Yesterday I tried to return my ten-year-old's too-small Croc slippers. It serves me right, I realise, for buying crazy overpriced plastic clown shoes. And believe me it will be the last time.

I'd bought a size 4 and required a size 5. Can I just swap them? No, not without the receipt. But I've lost it. Would anyone care if you just gave me the bigger size? The system wouldn't allow it, I was informed. It needed a receipt number. I had to keep my tiny Croc slippers and had wasted my £30.50. It was like the Little Britain sketch where the computer always says “no”; customer services organised for the benefit of the company, not its clients.

Ten years ago I would have slunk away muttering. But one of the few redeeming things about getting older, is knowing how to combat in-store injustice. I call for managers, demand head office numbers, plonk myself in the centre of the shop, unembarrassable, immovable, until finally I am handed a size-5 pair of plastic clown shoes. Don't mess with a middle-aged matron.

Christmas is when we are forced to confront new technologies. How many holiday minutes were spent poring over instruction manuals, trying to set fiddly digital clocks, fathom omni-function mobile phones? So I have two techno quandaries:

1) How do you teach children to deal with built-in obsolescence? My younger son was delighted with the iPod nano, bought with his own savings, until his brother received the new super-improved video nano. Do you tell a child to shut up and enjoy what he has? (Until it breaks — which with iPods will be any minute.) Or permit him to put his Christmas money towards buying the upgraded model and thus begin a life of perpetual dissatisfaction?

2) What is the assumed minimum technology owned by the modern citizen? And is it OK to discriminate against Luddites? Trying to park in the London borough of Westminster, I found the parking meters have been replaced by a large notice bearing a phone number. You pay to park by setting up an account on an automated line. It takes ten premium-rate, temper-fraying minutes. This is to thwart gangs who were sawing the tops off meters and bagging the coins. But effectively Westminster council has banned anyone without a mobile phone from parking.

Likewise the Government's new whizzy anti-global-warming TV ad, imploring us to ride bikes and not leave our tellies on stand-by, concludes by saying that more information is available on a website. No postal address, no suggestion that you pop into your library, no phone number, even. We must purchase to participate. Which in this case surely defies the point.

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