But because human being tend to focus on short-term benefits and our own immediate needs, such tragedies of the commons occur frequently .

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

I think we could get people to both be more productive and happier. We're less productive as individuals. We're less productive as companies, and we're more miserable.

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

When it comes to the mental world, when we design things like health care and retirement and stock markets, we somehow forget the idea that we are limited. I think that if we understood our cognitive limitations in the same way that we understand our physical limitations … we could design a better world.

Money is a great way to get happiness. Right? Lots of wonderful things you can do with money. The question is, are we really optimizing on that? So, if you think about getting lattes and getting cable. Which one of those is actually giving you a greater happiness, and if you have to cut on one of those, which one would you cut? So, I think thinking in terms of concrete terms would help us a great deal.

The people that lend you money basically give you an answer based on the risk that they are willing to take. But just because a bank is willing to take a particular risk doesn't mean that that is the right amount for me to spend.