When a habit emerges, the brain stops fully participating in decision making. It stops working so hard, or diverts focus to other tasks. So unless you deliberately fight a habit -- unless you find new routines -- the pattern will unfold automatically.

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.

I think I'm smart, and I know I was a good mom. But there wasn't a lot I could point to and say, that's why I'm special.

Rather, to change a habit, you must keep the old cue, and deliver the old reward, but insert a new routine.

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

Habits, scientists say, emerge because the brain is constantly looking for ways to save effort.

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.