Simmering tensions,a fling at the office party and families thrown together for weeks on end ... no wonder yesterday has become the busiest - and most lucrative - day of the year for divorce lawyers.
Even as Jackie Walker put the finishing touches to the sumptuous Christmas meal and table decorations, in her head she was making a life-changing decision. "We'd had the whole family over for Christmas dinner and I wanted everything to be perfect," says 47-year-old Jackie.
"But as I served dinner, I looked round the table of smiling faces and I felt like an outsider. I was putting on a happy face and fulfilling my roles as mummy, wife, daughter and daughterinlaw. But, God, I was miserable. As we sat down to eat, I thought about the looming New Year and felt: 'I can't do this any more.'"
And so, ten days later, as she swept up pine needles and took down the decorations, Jackie decided - like so many women in the post-Christmas period - that she wanted a divorce. "I'd been unhappy for a couple of years," admits Jackie, who has two children aged 11 and 12 with Mike, 44, a property developer.
"Mike and I had been so busy with our careers, the children and renovating our rambling 15-room house that we had no time for each other.
"There were times I'd think: 'What the hell am I doing with him when I might as well be on my own?' I didn't feel loved or adored.
"But it was only at Christmas that I realised how wrong it would be to keep up the pretence for yet another year for the sake of my children. So I sat Mike down and told him: 'This isn't working for me. Our marriage is over.'"
Mike was devastated but defiant. She recalls: "He told me: 'Jackie, I am the best husband you'll get and there will be no knight in shining armour to whisk you away, so you need to be sure of what you're saying.' But I was sure, so I filed for divorce."
Though some friends and relatives branded Jackie heartless for walking away after Christmas, it seems she is far from alone in her timing. Matrimonial experts have dubbed yesterday D-Day - or Divorce Day - because traditionally the most petitions of the year are filed on the Monday of the first full week in January.
In some years, the number is as much as 50 per cent more than in an average week. This year experts are predicting at least a 10 per cent rise on the norm.
Divorce lawyer Vanessa Lloyd Platt believes this is because the stress of playing happy families during the festivities can prove too much if a marriage is already teetering on the brink of separation.
"Only the stampede for the start of the Harrods sale is greater than the surge to file for divorce in early January," she says. "Most applications are from women reeling from the pressure of having to put on an act
over Christmas when they've been feeling unhappy in the marriage for a while.
"Often they will have approached the festive season thinking: 'I'll really make an effort at Christmas, but if things still aren't right by New Year then I'll leave.'"
This point resonates with Jackie, who now lives alone, near Edinburgh. "Christmas was magical when we first had our babies," she recalls. "But in 2000, when I turned 40, I had an overwhelming feeling that something was missing.
"I was the stereotypical middleaged, middle-class woman, with a great career as an event manager, a devoted husband, two beautiful children and a gorgeous detached home with a huge walled garden in a pretty village. But I wasn't happy and I felt terribly guilty for questioning my seemingly perfect life."
After admitting her feelings to Mike that year, the couple tried marriage counselling to salvage their relationship and for a time, Jackie says, they were happier. "Mike was hugely supportive, counselling made us refocus on each other and for two years things really were better.
"But when we moved house again in July 2002 they deteriorated dramatically. Once again, Mike and I were too busy for each other. I stuck it out, but by Christmas that year I knew things wouldn't change because my love for him had died."