Dopamine's primary role is motivation and drive, not pleasure or reward.

“Because ultimately, dopamine is not about feeling good, it's about feeling motivated. This is something that I've talked about numerous times before, but dopamine, contrary to popular belief, is not a reward molecule, so much as it is a molecule of motivation and drive. And the natural consequence of doing the exercise I just described, of writing things out that precede, are involved in the immediate execution of the habit, and follow the habit, will allow you to experience an increase in energy and thereby an increase in likelihood that you're going to engage in that entire sequence of events. And the reason for that is that dopamine gives us energy, and the reason for that is that the molecule epinephrine, adrenaline, is actually manufactured from dopamine. Biochemically, it comes from dopamine.”