Our petty lies say more about us than grand confessions

I did it again the other night. I told my stock lie – the one I've told so many times now that I'm convinced it's true. I can always feel it coming; the conversation veers into a particular area and it rises, tickly and unsuppressable as a sneeze. The challenge comes – "I bet you haven't even read it" – and out it tumbles: "Of course I've read Harry Potter."

It's just easier to lie. To come clean, to say that I'd rather go Dancing on Ice with Robbie Coltrane than immerse myself in the world of Voldemort and Dobby the House Elf, would not only seem dismissive, but exclude me from making any further criticisms of a book I don't need to read to dislike.

Everyone has a favourite fib – a petty lie that tells you more about them than any grand admission of adultery or fraud. My best friend persists in telling people he was at Live Aid, even though he was working in an office block in Canary Wharf at the time ("It's like Tourette's," he laments). A girl I know claims to be fluent in French ("Because if only I went back there for a fortnight, I would be"), while an old schoolfriend brags, pointlessly, about getting an A for his Art A-level ("Because I really should have done").

Sometimes – particularly in politics and celebrity – people lie with such conviction that it becomes a personal truth. Tony Blair drowned out any hint of self doubt at the Chilcot Inquiry with a tsunami of sincerity – unlike more blustering liars such as Jeffrey Archer or Bill Clinton with his evasions about the definition of sexual conjugation.

Then there are the collective lies, in which whole generations paper over their memories with something more colourful, whipping up nostalgia for events they never saw (witness the hordes of Baby Boomers who claim to have been there at Woodstock, seen the Sex Pistols or watched the Beatles play the Cavern). Lies of vanity (age, hair colour, dress size) are so prevalent as to be banal, as are the fabrications on matters of taste (hands up those of you who really enjoy Harold Pinter, Benjamin Britten or Brussels sprouts) and intellect (the 2:2s that so easily slip a gear and become 2:1s, the claims of Proust or Tolstoy as bath time reading).

As children, we learn the delights of lying, the truth of the proverb that "a lie can travel halfway around the world before the truth has got its boots on". Once you grow up, you learn the dangers, and not to fib too often. Still, that one stock lie remains a precious indulgence.

* Going to bed with Alastair Campbell is a curious experience. Pages 381-383 of Maya, the former spin doctor's new official work of fiction, might as well be headed: "THE BEST BIT". As soon as the ripping of silk dresses starts (which I'm pretty sure has never occurred in the history of romantic encounters), you know you're in for a feast.

Critics have enjoyed likening the book's hero, Steve Watkins – a quietly predatory figure not unlike Fitzgerald's Nick Carraway – to Campbell himself. But that would imply a talent for self-criticism not overly evident in his political persona.

* Friends of Madonna and Jesus Luz, her 23-year-old boyfriend, will be reeling from the news of their split. Dizzied, possibly still aphonic from the shock, they will be trying to make sense of the fact that 51-year-old Madge and the Brazilian model 28 years her junior weren't, after all, life partners.

Like the theory of turbulence or the cure for the common cold, this will be something that continues to baffle wise men and women for years to come. One small insight may come from Madonna's admission that: "We've just run out of things to talk about." But then, to find a man who doesn't get bored with her talk of Kabbalah and probiotic diets, Madge may have to pluck them even younger and even dumber.