On asserting "interestingness"

An epiphany while watching QI. An inviolable rule for teachers; never tell your class/audience "this is really interesting" before expounding on something.

It's a great example of two levels of communication at odds; a variation on the double-bind. If you have to tell them it is interesting, it isn't. Many years ago, a friend of mine was much given to this mistake, and it is only now that I realise that although some of what he said was indeed interesting, this "paradoxical operator" (hey--that's a good phrase--you read it here first) was always heard as the opposite, "Get ready for some boring stuff incoming!"

It is however OK to seek confirmation afterwards.

Isn't that interesting?