I’m British, was travelling in the states. Got talking to a guy at a bar while we’re waiting for service, and he recommended I try a pint of Guinness while in the US. He informed me they don’t sell Guinness in the UK.
I politely explained that they do indeed have Guinness in just about every pub in the UK. He disagreed, adding that he’s never been himself but his son in law went to London on business and told him so. I explained I’d lived in the UK including London my whole life. He looked at me lost in thought for a few moments, and said: “They don’t have Guinness there,” and walked away.