h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

At least I'd imagine it is, is pitching it at the right level for the group you are guiding. If people feel you are talking down to them, they would probably get fed up with it pretty soon. The same goes if you assume you know a great deal more than they do and you end up going over their heads and boring them stiff.

If you are showing a group around who you don't know and haven't met for more than 20 seconds, I'd imagine guessing the right level mightn't always be too easy.

From a customer's perspective, I know I've listened to some badly aimed commentaries. At the end of the day I chose to take the tour though, so I can't imagine why I'd be so hostile to the guide as to spit at him!