Why diet on your own?

So I must say that there are always commercials airing for specific diets or diet programs and they say that they are more successful than dieting on your own. I don't believe that. Dieting on your own allows you to learn how to change your life, the way you eat, and the way that you live. If you are following one of those fad diets, what are you supposed to do once you reach your goal weight? You then have to learn how to eat on your own and the chances of failure can be very high.