Oddly enough, I could not stand the sound of my mother's singing. This had nothing to do with the quality of her voice, nor with her ability to sing in metre and in tune, both of which were unimpeachable. It was the fact that she always adopted a "head girl", snobby sort of accent when she sang. This made me cringe to my toenails. She was an honest and decent woman, who normally spoke a clear variant of Southern English, which was impossible to localise. Her adoption of a class accent - on the the ludicrous assumption that those people were her betters - used to simultaneously repel and embarrass me. I can take on most of what has been written on this thread, but I did want to give an example of how getting it wrong can really annoy people. (I think UB40 sound just fine, by the way...)