What's the most important difference between traditional economics and behavioral economics? Conventional economics assumes that we are all rational. It assumes that every time we face a choice, we consider all the available options, perform a cost-benefit analysis, and follow the best possible path of action. Behavioral economics says that we act irrationally again and again because that's how our brains are wired. So, we make mistakes and work against our own interests.
That seems a bit depressing. Yes, but only by truly understanding our irrationality can we think about how to fix it. That's the great hope of behavioral economics.