I feel that two forces are at play here:
FEAR is the ultimate driving force behind every person's adherence to an organized religious belief system. Deep down inside we fear death, chaos, insignificance, solitude, suffering, and our personal weaknesses. Various organized belief systems in supernatural beings offer comfort answers to these fears; sometimes, paradoxically, by exacerbating those fears.
GUILT is the other force. It operates similar to marketing: First, create a need where there wasn't one; then, offer the product/service to satisfy that need. Take, for example, Christianity. By telling people they are hopeless sinners, Christian religions create a need for redemption in the eyes of the divinity. Once that need has been created inside people's minds, religions offer 'products' [Christ's ransom, for example] and 'services' [mass] performed by specialized agents [clerigy], in order to address the guilt of being a sinner. Guilt is exploited further by tying it with fear, as a system of reward / punishment is established to ensure that the believer is kept inside the flock [heaven vs. hell ; eternal life in paradise vs. eternal anihilation].
Eden