One of the saddest things about advertising

Is that, generally speaking, in order to do an effective job of selling products, advertisers are required to continue inventing new schemes to trick consumers into buying into the claims of their ads, because eventually, we wisen up.

David Lubars, a senior ad executive in the Omnicom Group, explains the industry's guiding principle with more candour than most. Consumers, he says, "are like roaches —you spray them and spray them and they get immune after a while."

This, obviously, was said in reference to advertising. From page 30 of Naomi Klein's No Logo (2000).