Clarkson on: the M1
Christmas is a religious festival where Christians celebrate the birth of their spiritual leader by getting together with their families, giving one another socks and arguing.
There is usually finger pointing over the turkey, and after lunch, warring factions gather in different parts of the house, whispering about how they never want to see one another again.
Mostly though, families can keep smiling through gritted teeth, never actually saying "Auntie, I hope this cracker blows your hand off".
On Boxing Day, everyone climbs into their cars and heads for home. This is when it starts to get difficult.
I have driven up the side of cliff faces in Iceland, and I have survived the Bombay to Pune highway in India, but for sheer lunatic driving, you can't beat the M1 on Boxing Day.
Husband is sitting there in his brand new woolly pully, telling his wife that he never wants to go to her parents again. After 15 years, he has just admitted that her mother is a fat, interfering cow who, he hopes, contracts BSE very soon.
She is crying and accusing him of not making an effort: "You know Daddy hates it when you call the Queen a lesbian".
The upshot is that he is not paying the slightest bit of attention to the road and hasn't noticed that visibility is down to two inches. He is still doing 90, relying on the glow from his new jumper for guidance.
No kidding. Last year, I was crawling down the inside lane doing 30mph, and there was a constant stream of over-burdened Volvos screaming past doing 90.
And then, south of Northampton when the fog lifted, I was making up lost time, going past the Volvos; and they had the audacity to indulge in some major-league finger wagging.
Well, they would have, except the row by this time had gone nuclear. She was on the mobile to the solicitor and he was admitting to eight affairs.
Even if there was a lull in the fighting up front, it would be filled with squawking from the back. Daughter had just broken the son's train who, in return, vomited on her new doll.
Further back still, the boot was loaded to the point where the car weighed more than an Intercity 125.
"On Boxing Day, everyone climbs into their cars and heads for home. This is when it starts to get difficult"
I find it little short of amazing that we can't drive while drunk, because alcohol impairs our judgement, and yet you are at liberty to drive around while getting divorced.
You are also allowed to drive while wanting a pee. When I go past a sign saying ‘services 30 miles' and I need to go, I will admit here and now that I will let my speed creep up to 130 and I will overtake on whichever side of the road I see fit. It becomes all-consuming to the exclusion even of life preservation. And when I finally make it, I will screech to a stop in a disabled parking bay. I do not think I am alone in this.
And I am certainly not the only person ever to have driven while suffering from hay fever. Last summer, I drove an 850bhp Nissan Skyline GTR even though I was virtually blind, a condition that became complete when I sneezed every four seconds.
Here's a fact: If you have a three- second sneeze at 60mph, you are blinded for a staggering 264 feet.
I will also admit to driving around while enraged by something on the radio and yes, I've turned round to check my daughter is OK on the back seat. I have also driven with a splitting headache. Only the other day, I had to pull onto the hard shoulder of the M40 where I fainted.
In fact, the days when I climb into a car feeling refreshed and ready to cope with diesel spills and people in hats are pretty few and far between.
And what about old people? If good driving is all about awareness and speed of reaction, then they should surely be taken off the roads. A 17-year-old youth just over the legal drink limit is going to be better able to deal with an emergency than the average, sober 70-year-old.
But there are no laws about driving while under the influence of Anthony Eden, or having a hay fever attack, or with a bursting bladder.
Which is why, when I hear the police are cracking down on people who drive around while talking into mobile phones, I laugh.
In the big scheme of things, this is not really so bad.