Harriet Walker: 'Why does Christmas bring on such torpor and agoraphobia?'

I kicked off the festive season by getting stuck in a lift, and I'm ending it stuck in an armchair, practically Velcro-ed in place by some malevolent superpower that dictates I can only watch TV, read my book and snooze with my mouth open. Why does Christmas bring on such torpor and agoraphobia?

"I'm only really going home for a day," one of my friends told me over a drink – our last chance to see each other before I turned into the lovechild of Scrooge and Jabba the Hutt. "I'm working up until Christmas Day and then I'm on holiday. And then we'll be at church, of course, and out on a hike on the day itself." My hair and nails practically retreated into my skin in horror. The thought of even venturing outside at this time of year makes me ill. My family spent Christmas playing The Beatles: Rock Band last year, a brilliant innovation, because strumming the plastic guitar gives some impression of exercise and hitting the little drums with a stick is practically a work-out.

So the fetid atmosphere and unintentional intimacy of a lift should have been perfect for me at this time of year. But it was very small, and also stuffed full of colleagues from The Independent. We'd been at a rather gluttonous drinks party, so our combined weight plus that of all the pigs-in-blankets and mince pies consumed, tipped the lift into creaking paralysis. That, and the fact there were 11 of us rather than the stipulated eight.

"Jump up and down all together to get it working again!" the host counselled through welded-shut doors. "Wrench them open with your nails!" demanded one of the more rapacious trapped journalists. "Why don't you play Angry Birds on my phone?" suggested one of the more tender-hearted among our number to a boy purpling with panic in the corner. Whether he was claustrophobic or journophobic, it was hard to tell. We had never seen him before and when we finally escaped, he was too busy being sick to answer. Escape we did, of course, rescued by firemen whose top lips curled at our quaking and screaming – and quite right, too: when the doors opened, we had only been about a foot from the ground floor.

I was amazed by my own reaction in that metal cube. At first, hysteria; swiftly followed by discomfort (high heels); anxiety, not at the reduced amount of space or air, but that I might throw up on a colleague; and finally, an overwhelming sense of frustration that this lift was simply not where I wanted to be for much longer.

Just like this armchair. I'm going to stand up now and put on some make-up, maybe even have a wash.

Right after this mince pie.