Advertising even the most clever, funniest, most expensive advertising can't make people buy something they don't want. It can create awareness of a product, it can even get people to come see the product. But if people know that they don't like or need the product, advertising won't help sell it. For example, look at a choice facing an electronics store. Why not advertise the best items, the product leaders that will draw people in.
Many people think that advertising is marketing.
Or that advertising is selling. You can use it to communicate what a product is, how it will fill a need or enhance life, how much it costs and where the buyer can get it. You can use it to differentiate a product or develop an image. Good advertising can create traffic, interest or an image. It can even position your product in relation to the competition.