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.

In terms of the actual curriculum for management education, my own view is very simple-minded: The world is incredibly complex, it changes all the time, and we should not even hope that we could create a general model that accurately describes the world in all its possible states.

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.

While we somehow understand revenge on an intuitive level between individuals, I do suspect that companies, assuming that people are rational, completely miss and underestimate the motivation people have for revenge.

Money is all about opportunity cost. Every time you spend on something, that's something you can't spend on something else.

None of us always make the best financial decisions.

Why would you take money out of your paycheck at the beginning of the month when you don't know how much money you'll need?