The problem with opportunity cost is that opportunity cost is divided among many, many things.

What you should do is wait until the end of each month, and then say, "OK, how much money do I have? How much do I need? Let me send the rest to retirement."

If we all make systematic mistakes in our decisions, then why not develop new strategies, tools, and methods to help us make better decisions and improve our overall well-being? That's exactly the meaning of free lunches- the idea that there are tools, methods, and policies that can help all of us make better decisions and as a consequence achieve what we desire-pg. 241

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.

Marketing is all about providing information that will heighten someone's anticipated and real pleasure.

If you think of people as making decisions actively, every time we think about the cup of coffee, we say, "How much will I enjoy the cup of coffee, what else could I not do in the future because I buy this cup of coffee?

The idea that you will make the right decision every time is very unlikely.