Went out with friends for a meal tonight. When the dessert arrived there was a strawberry and another fruit with it. They asked what it was, I quite confidently announced it was a syphilis. There was howls of derision. I can't spell what it really was!!
When I was in Switzerland a few years ago, I got rather angry when the Barman kept looking at me strangely. I gave my order for an apple juice quite distinctly.....a glass of pommes de terre please !