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.

It is facile to imply that smoking, alcoholism, overeating, or other ingrained patters can be upended without real effort. Genuine change requires work and self-understanding of the cravings driving behaviours.

Typically, people who exercise start eating better and becoming more productive at work. They smoke less and show more patience with colleagues and family. They use their credit cards less frequently and say they feel less stressed. It's not completely clear why. But for many people, exercise is a keystone habit that triggers widespread change.

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.

At some point, if you're changing a really deep-seated behavior, you're going to have a moment of weakness.

There's a natural instinct embedded in friendship, a sympathy that makes us willing to fight for someone we like when they are treated unjustly.

Habits are malleable throughout your entire life.