I've had the same problem trying to buy rock cakes - they look at me as if I'm a Cadbury's.  The most hilarious misunderstanding I was faced with was when I was desperately hard up - things haven't changed much.:-)

I had some jewellery and a few other items in my possession and needed to borrow some money from "Uncle".  After being unable to find it, I asked a woman if there was a pawnbroker in the high street.  She went bright red and snapped: "Certainly not!  Not in this area, anyway!"  and stormed off.  I laughed like a drain when it twigged what she thought I was asking!