I saw Josh White perform at Manchester's Free Trad Hall many, many years ago. At one point, while he was playing and singing, his top E string broke, He didn't stop, but simply reached into his pocket, pulled out a new string, and rethreaded it onto the guitar. And all whilst he was still singing and playing the guitar. Needless to say I was pretty impressed. Years later I mentioned this to a friend who had known White, only to be told that it was all part of his act and he did the same at every performance! What a performer.