People are powerfully moved by imagination, belief, and knowledge. They can consider the past and future. They can make changes in their behavior out of reason, in a way that animals can’t do.

I'm doing a lot of speaking and talking about habits, which is this subject that obsesses me. That's a lot of fun.

There's also something about your bed; it's sort of a symbol of yourself and of your marriage, if you're married. Making your bed doesn't seem to be an important thing in a happy life, and yet it can be that tiny foothold into a more orderly life that sometimes people need.

One of the great joys of falling in love is the feeling that the most extraordinary person in the entire world has chosen you.

Don't let perfect be the enemy of good.

Feelings follow actions. If I'm feeling low, I deliberately act cheery, and I find myself actually feeling happier. If I'm feeling angry at someone, I do something thoughtful for her and my feelings toward her soften. This strategy is uncannily effective.

Say “no” only when it really matters. Wear a bright red shirt with bright orange shorts? Sure. Put water in the toy tea set? Okay. Sleep with your head at the foot of the bed? Fine. Samuel Johnson said, “All severity that does not tend to increase good, or prevent evil, is idle."