The problem I have found with songs I have written sometimes is that I remember the (often several) revisions that a song has been through, and all it needs is a small slip into one of those revisions and all is lost, one is up a blind creek without a paddle. That is why I often have a set of printed words to hand because I would rather be embarrassed by having the words in front of me than by screwing up a song I love or worse one I wrote