In (or around) 1974, I wrote a song called "The Fool That I Was." It was just a lyric then, but I found a vocal melody that I still associate with the song. It was WAYYYY overlong, and not viable as a song for that reason, but it's not really 'shrinkable,' without losing too much of the story. It won't break into separate songs, and it won't tell an adequate story if I cut anything out.
I'm still proud of it, but what I've learned in the intervening years makes me acutely aware that it could become a poem, but not a song.