Willpower alone is often insufficient for smoking cessation, especially under stress.

“the first time I give up cigarettes, I focus on willpower, right? I say like, I'm going to resist I'm going to resist these cigarettes. ... And when my willpower gets taxed, my mother-in-law comes to town. I've had a really tough day at work. my willpower is really my muscle that muscle has been exercised all day. That's the moment that I give in and I pick up a cigarette and I say to hell with it.”