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

There's a second component of a good savings plan, which is something that a colleague of mine called Schlomo Benartzi and I developed many years ago, that we call "save more tomorrow."

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.

So the world is much more correlated than we give credit to. And so we see more of what Nassim Taleb calls "black swan events" - rare events happen more often than they should because the world is more correlated.

Investors must keep in mind that there's a difference between a good company and a good stock. After all, you can buy a good car but pay too much for it.

"Save more tomorrow" is a nudge to help people do what they know they want to do, which is save more, but they can't bring themselves to save more now. Just like many of us are planning to go on diets next month, or maybe in two months, certainly not tonight.

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?