[corobo]

Digging into the abstractions of life (with my admittedly non-medical non-scientific background) it seems that if you really boil things down it's all dopamine

Dopamine reward: Anticipation, something good happens, repeat

Addiction: Anticipation, something good happens sometimes, repeat

To answer the question from that standpoint, reward the player.. but not too much :)

Everything on top of that is there to get the person into the loop in the first place