The people that lend you money basically give you an answer based on the risk that they are willing to take. But just because a bank is willing to take a particular risk doesn't mean that that is the right amount for me to spend.

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

Not all debt is bad. From time to time we should get into debt when there's a good reason for that.

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?

For all of us, it's very hard to think about money, and because of that, we need help. In the same way that for all of us, it is hard to eat well, and we need some help. The poor have a particular challenge, which is that their life is actually much more complex - and they're much more complex cognitively.

The most difficult thing is to recognize that sometimes we too are blinded by our own incentives. Because we don’t see how our conflicts of interest work on us.

The bad news is that ignoring the performance of people is almost as bad as shredding their effort in front of their eyes. Ignoring gets you a whole way out there. The good news is that by simply looking at something that somebody has done, scanning it and saying "Uh huh," that seems to be quite sufficient to dramatically improve people's motivations.