As a social creature, humanity seeks peer approval in social situations. We see this in almost every aspect of social structuring. People seek the approval and well wishes of their peers and associates, and those that are outcast or shunned by their peers and associates suffer from this isolation. We tell stories to each other - we are a story telling species. We tell stories through words and art and acting and actions. But we seek approval for our stories. Great tales get re-told over and over - and they become the "Canon". Social Myths that meet the approval of groups get told over and over again, reinforcing this group approval of the tale. Embellishments and heroic actions get more approval, and are re-told far more often than stories of the mundane or ordinary.
As the descendant of a prey animal, humanity uses an Agent Attribution mechanism to fill shadows with horrors, rustling bushes with potential predators, half-heard sounds with inimical intent, half felt rhythms with projected animus. It is widely thought that our brains do this as a survival mechanism. To assume that all bushes with rustling leaves contain a jaguar that could eat us - simply makes us safer. Sure there will be false positives; certainly there will be rustling bushes that do not contain jaguars waiting to pounce on us and drag us off to be consumed. But many false positives, in this instances, are far more desirable than any single false negative. Thus our perceptual projection of "Agents in Bushes" acts as an evolved survival mechanism that helps protect us from danger.
It is also widely thought that humanity is the only species that binds time. We conceptualize yesterday. We conceptualize tomorrow. But this then brings up the question of tomorrow's tomorrow (and tomorrow's tomorrow's tomorrow...ad infinitum.) We have the concept of eternity...a shadowy, conceptual future that we can envision through recursive reasoning, but can't really picture in a mental map with any sort of realist predictability. Sure we might do many of the same things next Tuesday that we did last Tuesday, and maybe the next several Tuesdays will be very similar for us, but we can't really say that every Tuesday from now until we experience no more Tuesdays will be the same for us. Thus the concept of eternity becomes a shadowy cavern of potential actions and reactions. We can imagine events, but we cannot, with any accuracy, predict them.
Is it reasonable then to think that these three phenomena of human mentality (among many) have combined to have great effect on our history as a species? In conceptualizing "Eternity" (tomorrow's tomorrow's tomorrow's tomorrow's...tomorrow) with our ability to time bind, do we then instinctively need to attribute "agency" to that vast gulf of unknown, unknowable possibility? Do we "need" (instinctively, or due to evolutionary programming) to envision the jaguar in the bush of tomorrow? Further, in our capacity as a story teller species, do we then embellish the jaguar in the bush, turning it into a wondrous and spectacular Jaguar with mystical powers and supreme animus? What then if our peers and associates approve of our story, and re-tell it over and over and over - embellishing it as they go along?