One of the big lessons from behavioral economics is that we make decisions as a function of the environment that we're in.

In total, by giving people $30 bonus, Intel lost almost 5 percent of productivity. That's a lot. Now, think about it. You give money because you think this would increase motivation. It actually decreases motivation.

When you get a checking account, you should have a savings account, and the number for the savings account should be one off of your checking account.

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.

Dishonesty is all about the small acts we can take and then think, 'No, this not real cheating.' So if you think that the main mechanism is rationalization, then what you come up with, and that's what we find, is that we're basically trying to balance feeling good about ourselves.

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.

A very simple bad decision is to get into debt. And that is very expensive.