Candidates For The World's Worst Record

How about anything by Florence Foster Jenkins? In the 50's, RCA Victor released a compilation album of some of her material titled THE GLORY OF THE HUMAN VOICE????? She couldn't carry a tune in a bucket. In her private salon performances (in outlandish costumes), her pianist accompanist would make faces behind her back to the audience. She did have some formal music instruction in Europe (only after her dad died; he wouldn't pay for it when he was alive). They let her go shortly after enrollment.

On the other side of the coin, besides her very off-key singing, she was really happy with what she did.