Short story for a restaurant present in all possible timelines

There are a billion billion versions of this restaurant, and not everyone knows there are other timelines and worlds, but all the timeline travelers go straight to this diner in every timeline because it’ll usually be there, and it becomes a place for timeline travelers to meet and get food and such and try to figure out where they are and exchange stories about the timelines they’ve seen.

The owner realizes there’s something weird but mostly focuses on just serving good coffee and how to exchange all these weird currencies into his world’s equivalent currency (whether by selling gold or silver or whatever); and there’s so many of them who have never gone back to their timeline, who can’t because the chances are so tiny, that they could spend their entire life hopping and never hope to find it again. One of them was so excited because this world seemed really similar: it had the right number of Beatles and the right last three presidents, and New York was still named New York City and all that, but then they mentioned one tiny thing that the waiter boy didn’t know about it and it crushed this old man traveler’s heart.