I was joking earlier when I said that all writers are manic depressives, but it's a joke with a lot of truth behind it. For fiction writers and poets, too, there's something wrong with you and you do this art as a way of correcting it or addressing it in some way.
In the end, advertising rests upon the fact that consumers are a fickle and superstitious mob, incapable of any real judgment as to what it wants or how it is to get what it thinks it likes.