People are willing to work free, and they are willing to work for a reasonable wage; but offer them just a small payment and they will walk away.

One percent of people will always be honest and never steal," the locksmith said. "Another one percent will always be dishonest and always try to pick your lock and steal your television. And the rest will be honest as long as the conditions are right - but if they are tempted enough, they'll be dishonest too. Locks won't protect you from the thieves, who can get in your house if they really want to. They will only protect you from the mostly honest people who might be tempted to try your door if it had no lock".

The idea that you will make the right decision every time is very unlikely.

If you want to spend more money in restaurants, use credit cards more than cash. If you want to spend less, use cash more than credit cards. But in general, we can think about how to use the pain of paying and how much of it do we want. And I think we have like a range. Credit cards have very little pain of paying, debit cards have a little bit more because you feel like today, at least it is coming out of your checking account, and cash has much more.

The people who need to overcome temptation to the highest degree have the hardest time doing it.

We can think about how we reduce the pain in paying. So, for example, credit cards are wonderful mechanisms to reduce the pain of paying. If you go to a restaurant and you are paying cash, you would feel much worse than if you were paying with credit card. Why? You know the price, there's no surprise, but if you're paying cash, you feel a bit more guilt.

Money is a wonderful invention. It lets us save, it lets us specialize, right? I couldn't be a professor if there wasn't any money. Every day I would have to raise chicken and bread and broccoli and go ahead and spend all my time trading. So, money is a wonderful mechanism.