Take a Look at the Five and Ten by Connie Willis

Take a Look at the Five and Ten by Connie Willis (Asimov’s SF, November/December 2020) opens at a Thanksgiving dinner where Ori the narrator (a sort of adopted stepdaughter of the husband of the couple) has to cope with a variety of snooty and/or eccentric relatives: the wife and daughter are supercilious, the aunt constantly corrects and scolds everyone and laments the decline in standards, and Grandma Elving talks incessantly and with great detail about a Christmas job she had in Woolworths as a teenager. The wife can’t stand Grandma Elving’s endless stories and constantly tries to change the subject, but Dave Lassiter, the daughter’s boyfriend, is interested because he is studying neuroscience and is finishing a project on TFBM—traumatic flashbulb memory—and realises that Grandma’s vivid memories may be a case of that.
Then, on the Monday after the dinner, Ori gets a call from Gramdma asking for a lift to the doctors. However, when they get to their destination, Ori discovers that Grandma has arranged to meet Lassiter, who wants to interview her for his TFBM research project. The rest of the first part of the story sees Lassiter undertake many long interviews with Grandma, eventually becoming convinced that her intense memories are trauma related. Later on, after making little progress in discovering what the buried trauma might be, there are hints that it might possibly involve a young man called Marty who worked on the lunch counter with Grandma.
During this period Lassiter and Ori spend a lot of time together, and this is redoubled when Grandma suggests that they go to the city to look at the store to see if it will jog her memory:

The wind was definitely blowing today, a biting wind that whipped icily around the corners, but Grandma Elving didn’t seem to notice, she was so busy remembering what stores had once been there. “There was a shoe repair shop there,” she said, pointing at the Planet Fitness gym. “It had a neon sign that said, ‘Soles While You Wait.’ With a ‘U’ instead of the word You.’ It was right next to a Christian Science reading room, and I always thought the sign should be in their window instead.”
“What about the store?” Lassiter said, turning her wheelchair so she was facing the building where the Woolworth’s had been. “Do you remember where the door was?”
“Yes, it was right there,” she said, pointing at one of the windows of the 7-Eleven. “It was a big double door, and above it was the store’s name in gold letters on a red background—F.W. Woolworth & Co.—and in the corners, 5c and 10c,” and it looked like she was seeing it right now.
And seeing the whole store. “The candy counter was near the door,” she said, pointing, “and so was Christmas merchandise—tinned fruitcakes and bath sets and shaving mugs, and over in the corner was Gift Wrapping. I loved working in Gift Wrapping because you could see outside, the cars and the people hurrying by with their shopping bags and packages, all bundled up in their hats and scarves and boots.”
“Where would the lunch counter have been?” Lassiter asked.
“There,” she said, pointing to the left. “It stretched half the length of the store. It had stools all along it and booths coming out from it, like that,” she said, gesturing.
“And you and Marty and Ralph worked behind the counter?”
“Yes, I made the sandwiches and dished up the blue plate specials, and the boys grilled the hamburgers and hot dogs and made the fountain drinks, which was good. The first cherry Coke I tried to make, I got cherry syrup all over, and Marty said—”
She stopped short. “The cosmetics and notions departments were in the middle,” she said, starting again, “and over there,” she pointed to the right, “was Gloves and Scarves, and behind it was Stationery, which I loved working in because Andy worked there. He was so cute.”
“Before, when you were telling us about the lunch counter and Marty,” Lassiter said, kneeling down next to her wheelchair, “did you remember something?”
“No,” she said, but doubtfully, and then burst out, “It’s so maddening! Every time I think I have it, it disappears!  p. 179-180

After this they go and have lunch, where Grandma disappears into the loos for an inordinate amount of time leaving Ori and Lassiter together to talk. Then, when Grandma returns, she remembers the Christmas manger figurines she had been collecting at the time, and how Marty bought two of them for her. Subsequently she dispatches Lassiter and Ori to scour the thrift stores for a set, in the hope that the figurines will jog her memory. Eventually they find what they are looking for, and Grandma reveals that Marty died when he was young.
However, we eventually find out towards the end of the story (spoiler), when Grandma ends up in hospital during Xmas dinner, that she already has a set of figurines at home—and that the interviews, the trip into town, lunch, and the search for the figurines, and all the time that they spend together, was actually Grandma’s plan to matchmake Ori and Lassiter. And, worse, Ori learns that Marty wasn’t killed, which leaves her with the unenviable task of telling Lassiter that Grandma’s manufactured trauma is not true and that his research is based on falsified information, something that will likely cause him to fail his course.
The final part of the story reveals that Grandma’s vivid memories were created by a feeling of intense happiness while she stood at the door of Woolworths one evening. Ori has her own experience of this when she hears Lassiter say that he didn’t her earlier hypothesis that this was the case as it would have meant that he couldn’t go on seeing Grandma—and her.
This is a well told and entertaining romcom (the daughter provides a couple of amusing interference episodes during the story), and the evocative final description of Granma’s flashbulb moment, as well as Ori’s epiphany in the lift, are fittingly seasonal. They are also enough to overcome the late switcheroo of the trauma plot device.
I note in passing that this is a mainstream piece, not SF or fantasy.
***+ (Good to Very Good). 21,650 words.