Have you ever played runescape? As a kid, I was obviously a little confused initially by NPCs referring to "the first floor" of a castle/shop/etc meaning "the floor above the entry level", but it wasn't THAT hard for a 12 year old to contextualize "ah yes, this is a British game so it's a little different". (Admittedly growing up with british parents in Canada probably helped with understanding a bit, but I still don't think simply being aware of a few cultural differences to be impressive for anyone.)

If english speaking adult-aged people, with a wealth of opportunities to meet people and explore the world, are genuinely befuddled by en-GB to the point where they have to ask you to "translate" it, that's immensely embarrassing for them.