The situation is not helped by your children, who are supposed to be taking it in turns to open the doors. This will probably lead to a sibling war, resulting in a pile of ripped-off doors and a baby Jesus exposed weeks before His time.
You may find yourself bullied into buying versions covered with Teletubbies, Tweenies, Thomas the Tank Engine and just about every other copyrighted children's character that adds two quid to the cost of anything. And behind each numbered door lurks a chocolate. The children can't believe it. Fortunately, they will secretly scoff the lot in the first few days, thus getting further sibling wars over early.
But things could be worse. As you are absorbed in trying to order your mince pies via the Internet, their little voices might pipe up: "Mummy, can we have some coat hangers, tinsel and candles, please?" Now you think about it, there was a hornpipe playing softly in the background.
"Blue Peter Advent calendar, was it, madam?" asks the fireman as you watch his colleagues hosing down what's left of your home. As you sift through the ruins you realise that perhaps you should have supervised the lighting of the candles. But then the tinsel is practically unscorched and still attached to the coat hangers. It was just the rest - the tree, the cards, your curtains, furniture and photograph albums - that weren't flameproof.