Mental effort, I would argue, is relatively rare. Most of the time we coast.

That's one of the real dangers of leader selection in many organizations: leaders are selected for overconfidence.

A general “law of least effort” applies to cognitive as well as physical exertion. The law asserts that if there are several ways of achieving the same goal, people will eventually gravitate to the least demanding course of action. In the economy of action, effort is a cost, and the acquisition of skill is driven by the balance of benefits and costs. Laziness is built deep into our nature.

There's a very good reason for why economics developed the way it did, and that is that in many situations, the assumption that people will exploit the opportunities available to them is very plausible, and it simplifies the analysis of how markets will behave.

You should not take your intuitions at face value.

There is general agreement among researchers that nearly all stock pickers, whether they know it or not-and few of them do-are playing a game of chance.

you know you have made a theoretical advance when you can no longer reconstruct why you failed for so long to see the obvious.