Some years back I mentioned that while I generally love long ballads and songs I find "The Prickly Bush/Hangman Stay Your Hand" a boring song because it is essentially the same verse over and over and over. Someone replied that they had sung it at a school and all the children were enthralled and on tenterhooks wondering how the story would turn out.

See? As has been said above, it is a complicated mix of personal taste, the skill of the singer and the audience, familiarity and unfamiliarity, and many other more subtle effects. The actual length of it is one of the less important factors.