I was traveling in Hong Kong once, ages ago, when I ran out of toothpaste. I went to a convenience store, grabbed some, and when I went to check out, the clerk looked confused. She pointed at her teeth, then at me, in surprise. She didn’t know English, and I didn’t know Cantonese, so I pointed to my teeth and mimed, toothpaste, right? She furrowed her brow, unconvinced, but took my money.
When I went to brush my teeth later, the toothpaste had a strange texture and tasted awful. I asked my local friends to look at it, and they almost fell over laughing. Turned out it was denture cream.