My mom told me about an interesting incident that happened at work. Every evening, the workers are given Marie biscuits and tea. Some days back, they refused to have the biscuits, and were giving people a hard time.
When my mom went to ask them what the problem was, they said they're not going to eat Marie any more, since the people on tv keep telling them not to have it. My mom was taken back. She tried to explain how that is just an ad, and what Marie is trying to say is that there is now a new Marie, much better than the older one.
Uh-huh-huh, they simply refused to listen, and as a result, some other biscuit brand is used.
Sometimes, agencies try too hard. Ads do backfire.