To understand most important ideas in psychology, you need to understand how the mind is divided into parts that sometimes conflict. We assume that there is one person in each body, but in some ways we are each more like a committee whose members have been thrown together to do a job, but who often find themselves working at cross purposes.
The Happiness Hypothesis: Putting Ancient Wisdom to the Test of Modern Science (ed. Random House, 2015) - ISBN: 9781448166688