For example, Marmite Crumpets don't exist. You cannot buy them at the supermarket. To be clear: you can buy crumpets, you can buy marmite, you can buy butter; but you have to assemble them at home.
If you walk into a breakfast cafe, they will happily serve you sausage / egg / bacon / french toast / bubble / squeak (whatever that is). But no marmite crumpets. If you ask them to make it, they will give you a very strange look. It's not typically offered. It's something you just have to make at home.
It is unbuyable. Any tourist who comes to the UK to try a Marmite crumpet would need to bring a toaster or an oven with them, or quickly befriend a brit and hope that they have all the ingredients at home.
It's not a secret. You just can't have it.
*munches into crumpet thoughtfully, and salivates at the juicy savory delight, whilst staring at you pityingly and condescendingly*
Anyway, what's something that I could never experience unless I made it myself in your local?
Brother, we have all of those ingredients everywhere. We have a little British store run by expats who could get whatever packaged crumpet you use. Shit, I can make a batch of crumpets in about 15 minutes.
It's not like a crazy recipe that needs balanced flavors to be done right. Like I've never had a good poutine outside of Quebec. It's always sad beige gravy with the wrong seasonings or mozzarella or frozen fries or all of the above. It is never right.
What we can also talk about is local places making local dishes but they do it wrong and cheap or "good enough" and people come from abroad and try the dishes and think they're mid because they went to the wrong place.
TL;DR: I love poutine.
/Rant
We're talking British cuisine here
I had poutine at random place in Edinburgh which a Canadian friend said was the best poutine he'd had outside of Quebec. "Still shit though", in comparison to in Quebec
Down the Hatch?