"You are constantly re-inventing the tune, bending the notes to accomodate the sense of the words with each successive verse."
John's as good at getting the ideas right as he is at getting the notes right. The idea that a song has a single straightforward tune that should somehow be carried on unchanging from verse to verse is an absurdity dreamed up I imagine by lazy song-collectors. It still exercises an extraordinary tyranny over many (most?) singers and musicians.