Once my older brother took a taxi in Madrid. He often goes to the capital for business. During the trip he was called to his mobile phone. When he heard him talking, the taxi driver stopped and ordered him to get out of the cab. He had recognized that he was speaking Catalan.
While working as a waitress in Spain I was once asked by a fellow Englishman if I had ferrets and lived on a farm because I was from the north.
Also while working at the same job another English customer told me ‘oh, you’re actually quite intelligent despite your stupid northern accent’.
While working as an English teacher in Spain, a student once asked me why I didn’t ‘autocorrect myself and at least try to speak in standard English’.