The retail industry has its own headache: it loses $16 billion a year to customers who buy clothes, wear them with the tags tucked in, and return these secondhand clothes for a full refund.

Money are very difficult to think about. So, we think about money as the opportunity cost of money. So, we at some point went to a Toyota dealership and we asked people, what will you not be able to do in the future if you bought this Toyota?

We are all far less rational in our decision-making than standard economic theory assumes. Our irrational behaviors are neither random nor senseless: they are systematic and predictable. We all make the same types of mistakes over and over, because of the basic wiring of our brains.

Rainy day savings are incredibly important, because from time to time, bad things happen. And if you're not prepared for that, it's going to be really terrible.

The problem is that people basically dangle debt in front of us. And the cost for the poor of course is much higher than for the wealthy.

The companies that provide debt, what do you think their goal is? Is their goal for you to fully understand the cost of your debt? No. So they're basically creating these approaches to make you feel like it is incredibly cheap or just to think about the cost per day rather the cost per year or cost for a lifetime. So debt is very simple mistake.

If you think of people as making decisions actively, every time we think about the cup of coffee, we say, "How much will I enjoy the cup of coffee, what else could I not do in the future because I buy this cup of coffee?