Something that I didn't notice until I lived in the US was the implicit availability of standard ingredients, like graham crackers. So many classic American recipes are very simple but assume you have access to that one brand of canned pumpkin or cherries that everyone uses to make their pie with. It makes online recipes a lot easier.

A beverage example is the Piña Colada. The original recipe calls for Coco Lopez (see the Regan, The Joy of Mixology), and while you could substitute for some other coconut cream (confusingly, not cream of coconut), it's got the expected amount of sugar and thickeners in that make the classic drink. It's a specialty food in Europe and I assumed it was an antiquity, but no, our local supermarket sells it.