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.

You can think about life as a battle between you and a doughnut shop. The doughnut shop wants you to eat another doughnut and pay the money, and you want to do it in the short term, but in the long term it's not good for you either financially or from a health perspective.

When people are in severe pain, there's an expression, you're a "pain person," and what that means is that nothing else matters.

The major thing that holds you back when you're trying to change a bad habit like eating, smoking, or drinking too much is your belief you are out of control.

The problem with opportunity cost is that opportunity cost is divided among many, many things.

I don't want to say that the poor are inherently cognitively diminished, but at the end of the day of making difficult, tough decisions, it's very hard to have the energy to think about things with the right mindset.

When we save, everybody in the household is just suffering. By having the coin in a visible way, when you scratch, you can say the person that is in charge of the making money for the family is doing the right thing.