We hear a lot about rude shop assistants, but what about rude shoppers? Karen Falconer hears horror stories from the other side of the counter
It could have been a spoof of Are You Being Served? A customer flips his lid and rams a fellow shopper full frontal with a trolley. Hot, bothered and out of control: for this shopper the supermarket suddenly transformed into a battle field; other customers or sales assistants the enemy.

It's not an uncommon sight to see people tapping their feet in irritation as they queue at counters, or, indeed, to feel their glare as you choose a can of baked beans from the shelf where they want to be. Even to see a particularly flustered type let rip and tear strips off a poor shop assistant. For the customer is king and given this status, particularly on a hot summer's day, it's almost inevitable that some people will turn into despots.

But has our nation of shopkeepers turned into a nation of rude shoppers, where the people who serve us are treated with all the dignity of a Roman slave? "Shopper's rudeness is at its peak at sale time," according to Drusilla Beyfus, etiquette expert and author of Modern Manners. "A gluttony for possessions comes over people and they push and shove. They really fight: it's like territory in the First World War."

Sale time or not, I set out on the trail. My quest: the rude shopper. Sadly, I didn't have to look far.

In a large department store, I watched as several different customers approached a beauty counter, asked for help - without a "please" - and having received it with courtesy, simply wandered off without a "thank you". Young or old, and almost without exception, they did a cursory toss of the head, perhaps a little shuffle of the bum, and walked off. You'd have thought they were processing an order with an automaton, not some poor person trying to eke out a difficult living.

But how could women, who one minute were happily chatting to their shopping companions, so suddenly forget their manners? "That's nothing," confided a friendly face from the other side of the counter, looking round first to check her supervisor couldn't overhear. And out poured a string of stories, some more Molieresque than a 17th-century comedy of the mannerless. The tale of the "lady" who wanted a pair of Moschino sunglasses. To try them on, she wanted the security tags removed, which, officially, the assistant isn't allowed to do. She did it anyway. They weren't the ones she wanted. "Would you like me to cut off the tag?" volunteered the sales assistant as the customer picked up the next pair. "You can do what you want," was the curt reply. With training enough to overcome her bruised sensibilities, the young assistant said how nice they looked. "Look, my sister's got a pair. I know they look nice. I don't need you to tell me." Without another word, the woman made her purchase and left.

Then, there was the customer who walked in at 6.55pm, just as the store was about to close. "I bought this bag two months ago. But it doesn't match my shoes. Can I have a refund?" The well-heeled woman was duly referred to customer services on a different floor. She started screaming: "I'm on a parking lot! I'm not going up there!" Indeed, as the customer is never wrong, she got her refund, did the same little jig, and merrily trolled off.

For a shop assistant, the list of everyday anguishes is long. Every server tells a story. The scarves or jumpers that they've just folded in a big pile, only to have the next customer come and take an identical one from the bottom, so they have to start again. "They get you to get 50 out, then take the original one." The one who starts screaming as she walks through the door: "Can no one be bothered to help round here?". The shoe shopper who asks to see every pair in her size, only to walk out in a huff. The supervisor who was chased along 20 different cash desks by an irate male shopper. His wife returned later to apologise for him and explain they'd had some domestic difficulties.

Short of stealing, it really doesn't matter how rude or inconsiderate a customer is. Shop assistants have no right of reply. Effectively bound and gagged by the very precise rules of modern marketing - the customer, everyone knows, is always right - they are unable to defend themselves against a shopper's temporary insanity for fear of the sack. Were shop assistants monkeys, there would probably be a vociferous campaign to free them from their confinement, where, in the name of earning a few necessary peanuts, they are sitting targets for anyone and everyone's scorn, hostility or short temper.

But why do normal people turn into fiends once they enter a shop? Can it really be a game of bash the shop assistant's ego to bolster your own - because it's one of the few places where people feel they've still got some power?

For Robert East of Kingston University, a consumer behaviour specialist, it's at least partially to do with the dehumanisation of the shopping process: uniformed staff, computerised cash tills and the pressure to process customers as quickly as possible. "There isn't a very large interface between the customer and the seller, so there's not really a very human response," he says.

For Drusilla Beyfus, it is as much a question of let-down as it is of deliberate ego bashing. "There are lots of trigger points in shopping which can touch off someone with a short fuse," she says. "People go into shops hoping to give themselves a treat to ease the pain of life, then their nose gets put out of joint because they're thwarted by something. It reminds them that they're not going to get the treat they feel they deserved, and they behave appallingly. People are desensitised in public, and shopping is very impersonal."

Restrained everywhere else - people have to behave at work, with friends, even at home - shopping provides an almost unique scenario to let off steam. After all, there'll be no comeback as the shop assistants wouldn't dare retort, and no one actually knows you. To boot, staff are neatly depersonalised in their workplace garb. It's easy to forget that the person wearing it also has a couple of kids and a husband or wife at home. "Sometimes I think 'I may be a shop assistant but I'm not your personal slave'," says another sales girl, who thought it better not to be named. "I find myself saying that I'm a student - justifying myself, as if to say 'Look I'm not really a shop assistant'. One man actually said to me: 'What have you done to deserve this?' 'It's penance for my overdraft,' I replied. But customers don't understand how dreadful their behaviour makes you feel."

But are there really no subtle revenges taking place behind the smile: a short measure here or there, an extra pound on the bill, or even the sheer delight of telling some anti-social person who's just knocked over a pile of magazines to pick them up?

"Not as such," says John Rowland, an experienced hand who's run a retail framing business, Stegbrook, in the north of England for many years. "But we can have our fun, too. Once a couple spent 40 minutes after closing time arguing about whether they wanted a rather cheap picture, before leaving empty-handed." He simply mused. "It made me laugh. I've had that for one hour; she's had him for 30 years."

If nothing else, as you preen yourself for a shopping blitz, it's worth remembering that if you put your manners on hold, it's not the person you're chewing up that will look foolish, but you.

Shop assistants' Top 10 pet hates

Customers who ...

1 Never say please or thank you

2 Scream at assistants

3 Leave merchandise they don't want all round the shop

4 Demand things that the assistant isn't allowed to give

5 Come in just as the shop is closing

6 Take merchandise from the bottom of a pile

7 Lie about 'faulty' merchandise

8 Take their pending divorce/overdraft out on them

9 Keep changing their mind

10 Forget the assistant is human