2. We are what we do.
6. Feelings follow behavior.
From my personal experience and readings on psychology, this is definitely true. You do get sick if you fain sickness in order to evade school and you do get happy when you tell yourself so and smile, or at least try to smile, for several hours.
9. Life’s two most important questions are “Why?” and “Why not?” The trick is knowing which one to ask.
25. We are afraid of the wrong things.
... or the wrong reasons.