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.

But suppose we are nothing more than the sum of our first, naive, random behaviors. What then?

Money is very difficult to think about. So, we think about money as the opportunity cost of money. So, we at some point went to a Toyota dealership and we asked people, what will you not be able to do in the future if you bought this Toyota? Now, you would expect people to have an answer. But people were kind of shocked by the question. They never thought about it before. So, the most we got was people said, "Well, if I can't buy this Toyota, if I buy this Toyota, I can't buy a Honda." What is this thing? What is this value of price? Very hard to think about it.

People are irrational - and predictably so.

Imagine you owe on five credit cards, you owe five debts. So which debt should you pay first? And the answer is very simple: You should pay the one with the highest interest rate first. But that's not what people do.

Imagine you have six loans, small to huge. People want to close loans and because of that, they try to pay off the small loans, but that's not the right strategy. The right strategy, of course, is to pay the loan with the highest interest rate. People make this mistake and it costs them lots and lots of money, it's a very expensive mistake because interest rates accumulate and become very, very expensive very quickly.

When people are in severe pain, there's an expression, you're a "pain person," and what that means is that nothing else matters.