Dopamine is released not only when you experience pleasure, but also when you anticipate it. Gambling addicts have a dopamine spike right before they place a bet, not after they win. Cocaine addicts get a surge of dopamine when they see the powde, not after theey take it. Whenever you predict that an opportunnity will be rewarding, your levels of dopamine spike in anticipation. And whenever dopamine rises so does your motivation to act.
Your brain has far more neural circuitry allocated for wannting rewards than for liking them. Desire is the engine that drives behaviour. It is the craving that leads to response. The author also talks about temptation bundling.