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?

Once we start thinking of ourselves as polluted, there is not much incentive to behave well, and the trip down the slippery slope is likely.

We usually think of ourselves as sitting the driver's seat, with ultimate control over the decisions we made and the direction our life takes; but, alas, this perception has more to do with our desires-with how we want to view ourselves, than with reality.

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

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 things that motivate us are to help other people, to feel that we're useful, to feel that we're getting better, to feel that we are kind of living to our potential, to get a sense of meaning. All of those things are positive.

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.