Not really sure in this example which of us is the stupid foreigner....
A few years ago I was lucky enough to be staying for a while with my girlfriend in San Diego.
We became quite friendly with the Iranian owner of the local liquor store
One day we both walked in and asked if he sold any Pernod. He looked a bit confused but said that he might have some old stuff out the back and went off to take a look. My gf and I looked at each other a bit puzzled but I said perhaps he doesn't sell much of it and anyway it's not likely to go off is it?
He returned a short time later saying he didn't have any.
I asked if he could order some in as it is one of my favourite tipples and he was always helpful like that.
He explained how he'd love to help but couldn't really as it's not stocked by his suppliers but if I really wanted some he might know someone who could get it for me.
I said I was a bit surprised as Pernod was a drink you can generally find in the US and most countries.
Suddenly I saw the penny drop by the look in his face and his smile broke into a laugh as he said 'Pernod! Oh the drink. I thought you were asking for porno!'
I didn't enquire into the old stuff he thought he might have out the back
To finish it off in true US service culture style we had a bottle hand delivered to the house a few hours later free of charge with a note thanking us for the best laugh he'd had in ages