Well, these are the people that they are talking about. After carefully considering this question, it occurs to me that it is all about the pursuit of happiness and everything that flows from it. And lest you think that this an over simplification, I should assure you that it is not. It seems to me that the pursuit of happiness is serious business. Happiness is what is striven for after all of one's basic needs have been met.
Happiness is where art, philosophy, history, literature, the sciences, and mathematics reside.
Happiness is having contented, well-educated children. Happiness is being able to be with the ones you love. Happiness is self-actualization and fulfillment. So, therefore, achieving it can be a very tall order. As well it should be I suppose.