It helps if they can carry a tune and refrain from screaming to express emotions....Mariah Carey, Whitney Housan ,The Spice Girls and so on are guilty of this kind of thing. On the other hand, Celine Dionne can sing but I dislike her music. Maybelle Carter can't sing and I love her. Other "non singers" that I admire Billy Bragg Bob Dylan,John Prine. Frankie Armstrong must be one of the worst singers of all time...but she is grand. The best bad singer however, has to be Leonard Cohen....and he is wonderful.