Back around 1970 there was an ad firm that hired psychologists to determine exactly what would make people remember one product ahead of others in a particular genre. What they came up with was the original Ragu "mamma mia, that's a-one spicy meata-balla" commercial. People hated that commercial but Ragu quickly became the #1 selling spaghetti sauce in the country. I've noticed more and more commercials becomming more and more obnoxious over the years so maybe we will start to cycle back to a more intelligent composition.....Nahhh, why mess with success.
What they discovered was exactly what a couple of the slys have alluded to. That people (in the US), when faced with a number of products in the same category; cell phones or spaghetti sauce, will invariably buy the one that they have the clearest memory of from a commercial, even if the memory of the commercial is negative.