'Don't go there,' says a friend, darkly. 'I've spent all my life trying not to be like my mother. I hate the fact I look more and more like her. She's not a bad person, but I see us as chalk and cheese, and I'd hate to think I was anything like her. I feel like her sometimes - movements and expressions - but that's OK because I can keep it to myself, and only I know.'
My Mum and I both have a habit of rushing round when we're tired, like dying bluebottles, or toys running out of battery. We then blame the rest of the family for our exhaustion. It's weird - I know I'm doing it, and I know it's counter-productive, but it's as if it's been tattooed into my soul.
Sometimes similarities are physical. Find a picture of Tessa Dahl and you can see where Sophie gets her high cheekbones. Kate Hudson's smile is pure Goldie Hawn and Georgia May Jagger is the image of Jerry Hall. Sometimes it's just the odd facial expression. 'I look in the mirror,' says a work colleague, wild-eyed with panic, 'and I frighten myself to death. I think, oh my God, it's her.'
But is it so bad to end up like your mother? 'All women become like their mothers,' said Oscar Wilde. 'That is their tragedy. No man does. That's his.'
Maybe it depends on which habits we're copying. I read in the papers recently that Shirley Williams, who's now 80, went back to her home in the New Forest to plough her way through the vast amount of paperwork that made up Andrew Lansley's controversial NHS bill. It took her a week to work out that it was essentially a plan to dismantle the NHS. Then she spoke out against it. Wow, I thought. What dedication. At an age when you might be forgiven for doing nothing more than a bit of light gardening, there she was, grappling with public policy.
But then you remember that she's the daughter of Vera Brittain - the writer, pacifist and co-founder of CND. The habit of careful analysis was probably learnt in childhood.
When you're young, you want to be different from your mum. Similarities are frightening. Psychologist Terri Apter researched mother-daughter relationships for her book You Don't Really Know Me (W. W. Norton, £9.99). She says she has yet to meet a woman whose mother, for better or for worse, didn't play a central role in her development.
But it's a powerful attachment that's not easy to negotiate. 'Daughters,' says Dr Apter, 'identify with their mothers on a deep level, and fear that unless they make a deliberate effort, they will end up like their mother.' Teenagers work hard, says Dr Apter, to make their mothers realise that they're different, and to acknowledge that difference - which might explain all the high drama of slammed doors and confrontation.
But as you get older, you take a bit more of a long view, especially once you have children of your own. It feels sometimes as if your mother has leapt under your skin. All the excruciatingly irritating things she said when you were young now rush out of your own mouth as if you're reciting a particularly bad script. 'I keep saying, what's the magic word?' says the mother of two girls.
If you're lucky, you're able to stand back and realise that history's repeating itself. 'I said to my ten-year-old recently,' says Emily, 'that Justin Bieber sounded like a girl. It's just the kind of thing my mother said to me when she didn't appreciate that the Bay City Rollers were a giant musical talent.'
The mother-daughter relationship can get pretty fraught sometimes. One of my friends has a teenage daughter who, like her, is convinced that she's always right. 'Which isn't good,' says my friend, with admirable understatement, 'when we argue.'
But Mother's Day this Sunday is the time to celebrate all the good stuff. Mothers give you a whole load of baggage. As a teenager, you stand there, weighed down by this enormous rucksack clanking with enamel cups and tin forks and maps and torches and Mars bars, and you're desperate to throw it all away. You do chuck some of it out - the odd prejudice or unrealistic expectation. But later, much later, as you struggle through the howling winds of a horrible life crisis, you realise what that massive rucksack was all about. She was trying to pass on all the experience that could possibly be useful. You may never use the thermos flask, the safety pins or the packet of tissues. But she wanted you to have them just in case.
Now a mother myself, I am acutely conscious of all the terrible things I will pass on to my daughter (although she seems to be doing a pretty good job of ignoring my obsession with hoovering). I hope, as she gets older, she'll smile at my worst failings.
As Mr Bean said, looking at the picture of Whistler's Mother, 'families are very important. Even though Mr Whistler was obviously aware that his mother was a hideous old bat who looked like she'd had a cactus lodged up her backside, he stuck with her, and even took the time to paint this amazing picture of her. And that's marvellous.'
Or, as my lovely friend Gemma says of her own mother,' If I could do half as much with my life and be half as generous in the doing of it, I would consider myself hugely blessed.'