Being in a business that's largely image driven, advertisers often forget that an ad can be more than "cool" to be effective. There's a litany of emotions that are rarely touched on by ads for fear of alienating the audience. Any time an ad is too different, too trying, not cool enough, it can be squashed.
But this BBC report from The Why Factor shows how powerful other emotions can be. Namely, disgust. Disgust is visceral, immediate, universal (though what disgusts people varies greatly). People pay attention to disgust in a special way. That's why we can go on and on about what we hate but sometimes struggle to define what we like.
This isn't to say that disgust should be the only goal. For instance, you might not want to show a life-sized grasshopper enjoying a Dreamsicle on a hot summers day. However, it might be a powerful, unexpected place to tap in to for the right brand.
If disgust if the desired effect there's a fine line between disgust and shock. Shocking people can be good, it also gets attention, but it doesn't always make them feel. Shock is the effect, disgust can be the emotion. I think it's a pretty important distinction because it makes disgust weightier Something beyond marketing trickery.
I've embedded the episode for easy for listening. Thanks to @Copybeard for tweeting it.