The act of following a perfectly valid comment that would ordinarily spark debate with an idiotic question, thus derailing the entire conversation.
Peter: "I just heard in the news that oil prices are soaring."
Peter: "I said I just heard that oil prices are soaring."
Peter: "I just read it in the news, I'm trying to find out why."
Steve: "the government do that to the property market."
Peter: "Are we still talking about oil prices?"
Peter: "Stop being a Nigel!"
Peter: "I just came up with a way of solving world peace for all humanity."