Stuck in a jam as I was approaching a roundabout, I gazed idly out of the window. A car beeped behind. In my daze I’d not noticed that the line of traffic had advanced. I caught up with the queue and as I reached the junction the beeper pulled level, his face gargoyled with rage. “You stupid c***!” he screamed in my face.

As he careered off, adrenaline kicked in. For a second I considered pursuit, barging his Audi estate into the kerbside, leaping out Grand Theft Auto-style and then I’d . . . what? Kill him with a single deft blow? Rub him out with my Walther PPK? Instead I continued on a mission to the charity shop with my bin-bags of old tat.

But the incident left me oddly shaken. His obscene fury was so disproportionate to my offence. I hadn’t rashly pulled out, frightened or endangered him. I had merely delayed his progress by nanoseconds. Not even that, since I was still locked in a queue.

Sometimes London life seems built upon a thin and fragile crust through which a bubbling magma of anger could, at any moment, blow. Which is what happened in a baker’s shop a few miles from here last week when Jimmy Mizen, out buying sausage rolls with his brother, refused a challenge to a fight and instead had his throat cut with a shard of glass. And then in McDonald’s on Oxford Street on Monday when a row over a thrown drink ended with a man bleeding to death on the pavement, a knife in his heart.

When yet another young man dies, I scan the reports for words that will afford me some solace: gang slaying, feud, grudge, crack house, sink estate, 2am, drug-related, excessive alcohol . . . These words make me feel a little safer. They largely have nothing to do with my life. I can, I tell myself, protect my sons from these words. But when Jimmy’s mother, Margaret Mizen, said “it was anger that killed my son”, I know I am powerless. Because anger is unconfined: it lurks in the middle of the day, in public places; it erupts between total strangers. Anger turns a random encounter into deadly violence.

“There is too much anger in the world,” said Mrs Mizen. There is certainly too much in London. A friend, trying to cross a road, was hit on the shoulder by the wing mirror of a passing van: it deliberately swerved to wallop her. A guy at my gym says that out cycling he slapped the face of a delivery driver who’d honked at him. Aghast, I say he could have been stabbed, but he just makes a defiant, macho bring-it-on gesture, then admits he sped off when the driver began reaching inside his glove compartment.

A study by the Mental Health Foundation found that a quarter of us worry about how angry we feel. And yet just what are we angry about, with lives of unprecedented safety, surplus and comfort? I have always marvelled at the grumpiness of guests in luxury resorts: after a short time being waited upon in paradise, having flunkies pick up damp towels, one’s mood can be ruined by a deckchair being positioned at the wrong angle to the sun, a drink’s insufficient chill. Similiarly with our basic needs more than satisfied and our homes piled with consumer goodies, like brattish heiresses we rail against the slightest irritation.

I spend a ludicrous amount of my life angry about nothing much. Usually casual public thoughtlessness: mothers blocking small shops with their humungous £500 prams, nurses addressing dignified elderly ladies by their first names or, in my eco-wrath, anyone buying cases of bottled still water. Or brand new arbitrary regulations imposed seemingly to irritate and confound: such as Tesco’s policy of banning parents buying booze if accompanied by children.

Why do these things rile me? Because the world seems beyond control, the old certainties gone. Or am I just getting old? The anger management industry would, of course, have it that we are in need of their expensive ministrations. But are we really more angry or do we just express it more?

To lose one’s temper is no longer to be diminished or shamed; it is a sign of emotional health rather than a dearth of reason. All anger is righteous now. It is conflated with drive, passion, energy, a means to affect progress. Gordon Ramsay – whose confected ire is almost unwatchable – every week says goodbye to his F-Word celebrity guest with the catchphrase “Now f*** off out of my kitchen!” and we’re supposed to be endeared by his rough-diamond charm.

Anger becomes such a reflexive response that you do not realise how much it has penetrated your soul until you travel. Even New York seems less brimming with outrage, a collision in a crowd more likely to spark a “pardon me” than a glower. Visiting Australia, I heard a news item in which an educational survey had found modern Oz children the most illiterate and stupid ever. In Britain such a report would have provoked weeks of self-flagellating fury: Australia shrugged and headed for the beach.

Last summer in Slovenia, Europe’s most easy-going state, I was walking with my son past a line of cars when one started to reverse right at us. My London self banged hard on the back of the vehicle and made a furious hand gesture. The passengers in the car slowly turned, their eyes wide, their mouths agape at the crazy lady. “Mum,” said my son. “That was way too angry.”

Yes, I was London angry: the sense that everyone is out to shaft you, nip into your parking place, rip you off, frustrate your efforts to get home, grind you into the tarmac. Anger is the sound of entitlement, the urge to have your existence acknowledged. And for the young and poor and reckless, anger voices their lack of power, control, self-esteem. And, since it will swiftly meet the anger of others, it must be armed with fists and knives, guns and hard dogs.

Anger is a buzz, an addiction. Clearly we were designed for more than our modern functions. We are healthier, stronger, better fed and educated than any humans yet born. And yet we are the most underchallenged. Here we are, creatures capable of building cathedrals, surviving trench warfare or traversing oceans, wandering dead-eyed around B&Q. “People need to find peace, not anger,” said Mrs Mizen.

But alas “going off on one”– about Iraq, Cherie Blair, the tall, sweet boy in the bakery or the dozy woman driver in front – is the only time some people feel briefly and iridescently alive.

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