he card companies will often, as a courtesy, honor that credit card, but hit you with a penalty. And you keep swiping your card for $3 at Starbucks for your latté, and you're getting hit with a $25 penalty because it's over your credit limit.

It would be much more consumer friendly for them to beep you when you swipe your card that says, uh-oh you're over your limit, are you sure you want to use that?

If rather than setting the minimum balance as the lowest possible amount, so we keep people in debt for as long as possible, we raise the minimum payment and encourage people to pay off their credit cards, we're going to make less money, but we're going to have costumers that are more solvent.

So, what's a nudge? A nudge is some small feature of the environment that attracts our attention and alters our behavior.

The assumption that everybody will figure out how much they have to save and then will just implement that plan is obviously preposterous.

A good rule of thumb is to assume that everything matters.

I don't go by the ratings. I buy wine that tastes good. Statistically, anybody's ability to predict what will be a good wine a decade from now is limited.