"But it's only early November, surely they'll be stale by Christmas Day?" I murmured anxiously.
"Why not just eat them now?" she suggested.
"But surely it's bad luck to consume mince tarts before Christmas Day?" I protested, trying to revive an ancient urban myth.
Losing patience, she turned to serve other waiting customers, who clearly didn't share my concern with historic tradition.
As I left empty-handed, I thought I heard the shop assistant murmur, "nutter".
It's not surprising that calendar fixtures seem to come around at the speed of light, thanks to retailers' enthusiasm for proclaiming forthcoming events months before the actual day.
I've already attended my first Christmas dinner, which included turkey, ham and all the usual festival knick-knackery such as candles and crackers on the table.
I've never expected too much from the headwear that falls out of a Christmas cracker, but this year, Chinese manufacturers have taken traditional party hats down to even more abysmal levels of tawdriness, replacing paper with some sort of disgusting transparent plastic.
A traditional crown cut in gossamer-thin plastic somehow doesn't press any festival buttons. My dinner companion, a barrister, suggested the limp-looking hat looked more like a condom. I agreed and decided to fold it up neatly into a small square and slip it into my wallet, in case I got lucky later in the evening.
In an effort to try to slow down retailers' enthusiasm for marketing events months ahead of time, I've decided to ask my Member of Parliament to introduce a bill similar to the law that restricts the sale of fireworks to a three-day period.
Imagine a blissful world where we didn't have to listen to Jingle Bells or White Christmas every time we entered a shopping mall for the best part of two months.