Stymied by kids jokes
Twenty years ago I wanted to move to Paris to live with my beautiful and successful French girlfriend. To get a job there you have to have perfect French, which I didn't, so studied hard reading French philosophy books, technical books and watched French films and TV without subtitles. I was feeling confident and even started thinking in French.
Then my woman sent me a bag of sweets with a childish joke on each wrapper. I couldn't understand any of the jokes, couldn't guess the idioms or puns, and realised I was never going to France.