One of the worst singers I've ever heard used to perform at folk clubs in Reading in the early 1970s - and always went down a storm. He was a Geordie, and sang Geordie songs ("Keep your feet still, Geordie hinny" and the like) without any two notes following in the same key. He was so bad that he was good, if you know what I mean. After the initial stunned silence not even normally polite folkies could restrain themselves, and of course at the university folk club I'm afraid we showed no mercy, and laughed throughout. But he didn't seem to mind, he was certainly always willing to come back for more, and people enjoyed his performance precisely because it was so bad.

Of course it couldn't last. With practice his singing improved to the point where it was merely bad, rather than hilariously awful, and his star faded.

I've always felt rather guilty about laughing at him, although it was impossible not to. But he was enjoying himself and entertaining his audience, so despite being a bad singer you could say he was a good performer.