In his book, All Marketers Tell Stories, Seth Godin talks about understanding why people buy the goods and services they do, He states that: We believe things that aren’t true …or many things that are true, are true because we believe them. 

In other words, we believe what we want to believe, and once we believe something, it becomes a self-fulling truth. For example, why do people buy bottled water when they can get it for free?

One reason is that we have moved beyond buying things we need and have moved to buy things based on our complexity of wants. If you believe that bottled water is better and you want better water, you happily buy it and also enjoy the statement the product makes to others.