The test of learning psychology is whether your understanding of situations you encounter has changed, not whether you have learned a new fact. - Daniel Kahneman

When forecasting the outcomes of risky projects, executives too easily fall victim to the planning fallacy. In its grip, they make decisions based on delusional optimism rather than on a rational weighting of gains, losses, and probabilities. They overestimate benefits and underestimate costs. They spin scenarios of success while overlooking the potential for mistakes and miscalculations. As a result, they pursue initiatives that are unlikely to come in on budget or on time or to deliver the expected returns — or even to be completed. In this view, people often (but not always) take on risky projects because they are overly optimistic about the odds they face. I will return to this idea several times in this book — it probably contributes to an explanation of why people litigate, why they start wars, and why they open small businesses.

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.

People tend to assess the relative importance of issues by the ease with which they are retrieved from memory — and this is largely determined by the extent of coverage in the media. Frequently mentioned topics populate the mind even as others slip away from awareness.