Inspired by this bloke
Who's been interviewed around the world as an expert on the Royal Family, talking in an upper class English accent only for people to find out he's actually Tommy Muscatello, a 38-year-old Italian-American who grew up in upstate New York. (https://www.theguardian.com/uk-news/...sex?CMP=twt_gu)
What's the highest level/important job you think you could get away with calling yourself an expert in if no-one ever looked into your background? I once convinced someone that I was Didier Drogba on the night that Chelsea won the Champions League so I feel I could definitely get away with it but not sure in what subject I'd excel.