So is it possible to nurture a relationship between the child you love and their grandparent(s), who you can't bear?
"I had a formal relationship with my grandparents when I was growing up, largely because they lived far away, and I didn't want that for my own children," says Lisa Parks, mother of two boys aged eight and six.
With Lisa's own parents living the other end of the country, this leaves her in-laws, who live just round the corner. "This should be ideal, but I don't get on with them at all. They are homophobic, racist and think it's OK to swear in front of our boys, as well as criticise my parenting and only give the boys ice-cream for tea. Every three or four months, we wind up in a huge argument about something," she admits.
Despite the animosity, Lisa still feels strongly that her kids have a right to know their family. "But my god, it's a hard balancing act," she admits.
Lisa is not alone, says psychologist Carol Burniston. "The in-law relationship is complex and often troubled and although people usually focus on the jokes about men and their mothers-in-law, it's the relationship between women and their mothers-in-law that can be the most unsettled, particularly when the woman has children."
On the emotional side, the mother-in-law may see you as competition for being the closest woman to her son – or perhaps it's vice versa, with you seeing your mother-in-law as hot competition, says Burniston. "That alone can lead to jealousy and competitiveness."
Then there's the culture of the family – issues around the way people conduct themselves and styles of doing things. "If it's very different in the two families, it can cause disagreements. For example, perhaps you focus on healthy eating, whilst Grandma gives your kids endless sweets and sugary drinks."
The third most common area of contention is perceived preferential treatment, says Burniston, with many people feeling that their parents-in-law favour another person in their generation.
"My mother-in-law makes it very clear that she thinks her own daughter is the most fabulous mother, while I'm anything but in her eyes, and that alone can be hard to stomach" says Lisa.
Making matters worse is that many women admit they have a tendency to turn into ogres themselves in the company of their in-laws. "I don't like the person I become when I'm around my mother-in-law. I start being bossy and prickly, which is exactly what I complain she's like," says Louise Jeffers.
"Every time I leave their house, I think to myself, 'Why was I like that?' I want my kids to have a close relationship with them because my grandmother was such an important influence in my life, yet in practice I don't seem to make it easy."
Psychologist Lynne Jordon says this is common. "Threat brings out the worst in us," she explains.
Her advice is to try and understand where difficult in-laws are coming from. "Step back and see things from their point of view."
It's easier said than done, she admits, but it often shines a valuable light on their views and decision making processes.
Psychologist Michael Sinclair agrees. "Rather than constantly pointing the finger, whether out loud or in your head, be curious about them. You may even want to ask them what's behind their decisions if it's appropriate. If they are unreasonable, by all means be assertive, but still be empathetic as the communication will be far more constructive."
Don't sweat the small stuff, adds Burniston. "We can all be guilty of letting petty things irritate us, but children soon pick up on the tension that causes and you wind up making their relationship with your in-laws anything but relaxed and easy."
A good tip here is to ask yourself if a friend did the same thing, would it really bother you? We often have different rules for our in-laws because we start off with our backs up, explain Burniston.
Pick your battles, she advises. "It's only when something genuinely matters that you should confront it. If it doesn't really matter, let it go."
Jenni Trent Hughes agrees. "My mother-in-law used to insist that I rub whisky on my son's gums when he was teething," she says. "After a few weeks of battling away and listing all the reasons why I thought it was the most scandalous suggestion I'd ever heard, I just said, 'Thank you.' She then smiled, was happy, and that was the end of that."
If you need to offload, talk to friends, not your partner, says Tim Martin, therapist at Harley Street Mind Boutique. Your partner may be the nearest and easiest person to talk to, but it's not fair – these are his parents.
Offer your in-laws the opportunity to spend quality time with your kids on their own, he adds. "This will enable your children to view their time with their grandparents in a positive way, without influencing them with your own thoughts and emotions."
Jenny Squire couldn't agree more. "I adored my granny, but my mother – who clashed terribly with her – wouldn't ever let me get close to her. Granny used to invite me for sleepovers, but I wasn't allowed. Granny used to invite me round for tea alone after school – as she lived a few doors away – but again, the answer was no.
"She died when I was 19 and I still feel sad I missed out on the relationship, particularly as my mother doesn't seem to have a good reason for standing between us. 'I just didn't like her much, so assumed you wouldn't,' she usually shrugs. I still resent her for it."