This is your System 1 talking. Slow down and let your System 2 take control.
-- Author (Chapter 1 paragraph Page 29)

Importance: The author provides an example that illustrates the function of the two modes of thinking. System 1 is fast and reactionary. System two is plodding and thoughtful.

Highly intelligent individuals need less effort to solve the same problems… A general ‘law of least effort’ applies to cognitive as well as physical exertion.
-- Author (Chapter 2 paragraph Page 35)

Importance: System 2 thinking requires more energy than System 1 thinking. The author points out that highly intelligent or talented individuals exert less energy to solve problems than the average person because the System 2 function required to solve the problem comes to them much easier due to their high level of intelligence or natural talent.

Unfortunately, she tends to say the first thing that comes into her mind. She probably also has trouble delaying gratification. Weak System 2.
-- Author (Chapter 3 paragraph Page 50)

Importance: The author describes an individual who allows her System 1 reactions and responses...