Kris, I think it's something about the way some people sing the 'carrier bags' line in five syllables rather than the more natural (I reckon)4.

And I agree - I hate singing it, it's always asked for, I hate other people, but it's different when the man himself does it (although when he performed here one time they got the local primary school kids to sing along with him and that was pretty excruciating).

Maybe John G you haven't heard much of his material, or seen him perform.