When I go grocery shopping, I often take with me canvas and tote bags for my groceries. These are usually conference freebies and marked with all sorts of vendor names, etc. I place them on the belt before my groceries. Pretty clear, right?
One day I was shopping at a Price Chopper supermarket. I placed the bags on the belt, and when the cashier asked if I wanted paper or plastic, I just answered plastic, assuming that she was asking what I wanted after my bags were filled.
When I turned back around, I realized that she had neatly folded all my bags, placed them in a plastic bag, and then proceeded to pack the rest of my groceries in plastic bags.
And she was just so NICE, but she was so clueless when I tried to explain to her what they were used for. I found out she was a new cashier, but you know, its not that hard of a concept.