1.
I think self-discipline is something, it's like a muscle. The more you exercise it, the stronger it gets.
Daniel Goldstein
2.
Psychology, unlike chemistry, unlike algebra, unlike literature, is an owner's manual for your own mind. It's a guide to life. What could be more important than grounding young people in the scientific information that they need to live happy, healthy, productive lives? To have good relationships?
Daniel Goldstein
3.
If you set goals for yourself, and you're like a lot of other people, you probably realize it's not that your goals are physically impossible that's keeping you from achieving them; it's that you lack the self-discipline to stick to them. It's physically possible to lose weight. It's physically possible to exercise more.
Daniel Goldstein