I stood in Pak 'n Save, weeping into a Terry's Chocolate Orange, rocking slowly backwards.
A lady with a trolley was trying to ease past, "scuse me, darl ..." I seized her by the throat, pinned her against the cereal and cried, "but it just doesn't feel like Christmas". Then I curled into a ball on the floor, gibbering and chewing the cornflake box.
Oh yes, it was Christmas.
Any Kiwi with a British friend will have seen the scene this Christmas. Christmas is the time of year when the British in New Zealand start to crack up. You'll see them pacing up and down, muttering: "But it just doesn't feel right ..."
It took me years to work out why this happens. As someone who grew up in England, I've had a string of Christmases here where I just felt odd. But this year, I worked it out.
Dad dragged us off to some distant city down south for Christmas. He likes to take us to places where the pharmacy is a tourist attraction. We were told that we simply had to see the local mountain, so up we drove.
Then we got out of the car, and I realised I had to walk up a peak.
That would have been ok. Except that I was wearing a pencil skirt and new flats. See, I'd fallen victim to English woman on weekend away syndrome. I'd packed clothes suitable for lounging on a yacht in Monaco. (Not that I've been to Monaco, but I've planned extensively for the situation when I meet the Prince of Monaco in the dairy.)
The tangled grass of the mountainside was slick with rain and pebbles. I looked at my new, patent leather, Boxing Day sale flats.
Something told me the mountain wasn't going to be impressed.
Two country Kiwis strode past in ex-Soviet Army boots. The woman gave me a pitying look. "Poor Jafa," the look said, "if we left her alone she'd be found dead two weeks later, suffocated by her own lycra pencil skirt. Perhaps we should be kind and just set the pigs on her now ..."
It was true. At the top of the hill, I realised that being mauled by a wild boar would have been a less painful experience.
I also realised that English people are pretty much always townies. And that is why in summer you find dazed and confused Brits.
In summer, New Zealand loves to go outdoors and throw itself at things. Running, biking, skiing, surfing, strapping yourself to a large hanky and throwing yourself out of a plane - these are things NZ excels in. Every summer, you'll see families stuffing the car. They're off to carve out a space in the great outdoors.
If they're not at the beach, they're on the farm. It seems everyone knows someone with a farm.
But for a chunk of Brits, these outdoorsy pastimes aren't a normal part of life.
Firstly, most Brit expats probably came from suburbia. In 2015, 90.6% of Brits are predicted to live in a city. So riding through fields, or even seeing a field, isn't normal. And, given Britain's weather, how likely is the beach?
Plus, the UK doesn't have the sizeable agricultural backbone that NZ does. The UK's top three exports for 2013 were metals, machinery, and oils. NZ's were dairy products, meat and timber. The NZ economy depends on people being outside and farming the land. Britain's doesn't. That's got to bleed into your cultural landscape.
Lastly, pastimes like hunting, skiing, horse riding and fishing can carry aristocratic images in England. They're for people with double-barrelled surnames. They're not for your middle-class kid on a summer holiday.
In summer, NZ collectively moves outside. It roasts, like a parsnip, in the wild outdoors. Not having a farm or bach to go to, or knowing what they'd do if they had, Brits are left feeling confused.
The old hands who know the drill find Kiwi mates to tag along with. Or will have gone overseas.
But there'll still be a bunch left, looking dazed and crooning to a squashed box of McVities biscuits.
So, if a Brit crawls into your lap with a whimper this holiday ... be kind. It's the strange season for expat Brits.