As the tills finally fall silent on Christmas Eve, commercialism and cynicism tend to wash away. Families, who may see each other seldom and like each other little, nonetheless gather to renew the ties that bind. There are traffic jams in all directions.
There are many who, like Peter Atkins (right) do not buy the religious message of Christmas. But most of us buy the social and biological one: that families matter.
Paradoxically, as nuclear families dissolve into complicated extended networks of steps and halves and in-laws, they may come to matter more. They may also become better at offering support that is not too claustrophobic, demanding or judgemental.
They may need to. Welfare and other subsidies - like free higher education and student grants - are being pushed back to become closely-targeted help for those in need. The run-up to Christmas has seen the unveiling of pension plans that are intended to increase young people's contribution to pension funds.
They will add new demands at a time of people's lives when they will still be burdened with debt from their students years. To try to ease the load more students will live at home, and more parents will go on supporting their children for longer.
As the government's welfare-through-work policies kick in, parents of young children need their own parents more to help care for the children. As hospital care for the old becomes rarer, and institutional care - never ideal anyway - gets more expensive, more children will be looking out for longer-living oldies. The burden of welfare is being pushed back on to families and pushed down the generations to the once-privileged young.
It all sounds pretty grim: the family as last resort, the place, as Mrs Thatcher once famously put it (and got herself roundly mocked) you go when you have nothing better to do. Families may be horribly "familiar", sometimes stressful, often boring, embarrassing, inconvenient.
But for young adults having a safe place to go where you are uncritically welcome allows adventuring. For children, no one has yet dreamed up a better way to grow up. And probably for more people than care to admit it, family make the best friends.
But families are changing - and the change is fuelling academic furnaces. Earlier this month contributors to the British Psychological Society's conference were, appropriately enough, sounding off on family matters from hard-to-manage four to six-year-olds through the drinking habits of adolescents to Judy Dunne's study at the Institute of Psychiatry on step-families and the impact separation of parents has on children's development. This draws on a huge longitudinal epidemiological study of 9,000 families and a detailed study of 20.
One of the findings: that fathers matter too.
Such work is needed to inform thinking on tax, welfare, student support, legal reform, housing, health and in other areas if policies are to be devised which at least take account of how things are before seeking to tip the balance in favour of how people think they ought to be.
So as the women of the world (and celebrating the birth of a baby makes Christmas a women's festival) embark on their annual matriarchal power trip, forget the irritation. This is the warm bit which banks the fire against the cold. Families in the future, whatever their ramshackle state, are going to be taking on more strain than they have in the past few decades.
Happy Christmas all.