If you want to do something that requires willpower - like going for a run after work - you have to conserve your willpower muscle during the day.

Shampoo doesn’t have to foam, but we add foaming chemicals because people expect it each time they wash their hair. Same thing with laundry detergent. And toothpaste—now every company adds sodium laureth sulfate to make toothpaste foam more. There’s no cleaning benefit, but people feel better when there’s a bunch of suds around their mouth. Once the customer starts expecting that foam, the habit starts growing.

Cravings are what drive habits. And figuring out how to spark a craving makes creating a new habit easier.

Most of the choices we make each day may feel like the products of well-considered decision making, but they’re not. They’re habits.

For a habit to stay changed, people must believe change is possible.

There’s something really powerful about groups and shared experiences. People might be skeptical about their ability to change if they’re by themselves, but a group will convince them to suspend disbelief. A community creates belief.

What we know from lab studies is that it's never too late to break a habit. Habits are malleable throughout your entire life. But we also know that the best way to change a habit is to understand its structure - that once you tell people about the cue and the reward and you force them to recognize what those factors are in a behavior, it becomes much, much easier to change.