Some professors from Ivey Business School have written a nice little PDF e-book about behavioral economics. Behavioral Economics for Kids
As you read it, you may think that you have heard some of these things before, from sociology, from anthropology, from psychology. And indeed you have.
What you are hearing now are things about how humans behave that were figured out by economists.
Essentially where we are now with this stuff is that economists seem to have finally determined that rational theories of behavior are in fact not descriptive of reality. Other disciplines knew that, but we are finally getting some convergence of research. So this is a good thing. But it isn't all new.
Documentation of the weirdnesses of human behavior goes much farther back than modern academe, actually. Remember Aesop's Fables? Think of the ancient Greek philosophers, think of Machiavelli's advice to the prince, think of Shakespeare's portraits of human frailty, and you will see that our fondest subject of study is ourselves.
One thing that the label of behavioral economics has done is to make the whole science of human behavior sound a ton more substantial, and more businesslike. People who would not consider hiring a psychologist for marketing advice are now willing to hire a behavioral economist. (Sounds rather like branding, doesn't it?)
If rational thinking were always at work, there would be little fun to be had in marketing, advertising, entertainment or art. Fortunately, human beings are hardwired for some of this stuff. And I get to keep my job as a qualitative specialist. Yay!
(It's still a fun read. Not long, and has some lovely simple explanations.)