Is it "better than a poke in the eye with a sharp stick", or "better than a poke in the eye with a blunt stick"?
I suspect that some sort of metaphor testing facility in the Discworld concluded that virtually anything was better than a poke in the eye with a sharp stick, but apart from that I'm not 100% certain.
Side question: is there a term for when a metaphor or cliche gets mutated?