You made it all up ! "Original sin"
Unlike the truth, which does not adapt to anything but reality, belief systems can evolve because they do not have to adhere to reality at all. But this means that belief systems do not fulfill actual human needs. Fulfilling an actual need does not require belief at all. Some pseudo-scientific belief systems try to fulfill actual needs (such as, say, cancer), but they do so by presenting a more fundamental imaginary need (such as getting your spinal column into alignment, to preserve "holistic" health).
The most leverageable needs are those that are invented, manufactured. Real needs can generally be fulfilled in many different ways. If you can, however, convince people that they have a pressing need that only you can fulfill, then you place yourself in a great position to manipulate minds. It is the strength and scope of the invented need, and the exlusivity of the solution, which makes religion so attractive. The fate of your eternal life is in the balance, and you must believe in a specific god in a specific way in order to get the upper hand.
So we have two ways of relating to other people : on the basis of real needs, or on the basis of imaginary needs.
These imaginary needs, of course, do not come from thin air. Their cornerstone lies in basic human emotions - the ever-popular FUD (fear, uncertainty, doubt), the desire for specialness and validation, moral anxiety, guilt, and so on. Christianity, for instance, is based on the imaginary need for "salvation", which is needed because man is fundamentally depraved, headed for eternal hellfire, and needs guidance in life. This appeals to pretty much all the tricks in the book.
You have to make the individual believe that people (usually including themselves) are in some way depraved or flawed. This will naturally appeal to those with low self-esteem and low ego, perfect targets for your belief system. Having manufactured the need, you can then make them believe that only you can provide the solution that works.
Here are the imaginary needs filled by major beliefs and belief systems (and note how some of these contradict outright) :
Monotheism - Man is born in original sin, which is a yoke on every single human being. Man's values are natural and therefore depraved. Everyone is sinful, and need religion to be "saved" from himself. This salvation inevitably has nothing to do with the sins in the first place.
Greenie - Man's values are unnatural and therefore depraved. Man should rather live in harmony with nature to "save" nature (especially cute animals, or animals with a face) and be "saved" from his own folly.
New Age - Man's evil modern progressist values have pushed him away from communication with some overarching natural principle, usually rooted in the ancient past. The solution is to reconnect with that principle, while giving lots of money to a guru who buys himself evil modern progressist cars.
Buddhism - Your values are too unnatural and are not in harmony with the tao. Meditate more. Maybe, just maybe, you'll stop reincarnating into small animals some day. But keep your pet hamster close at hand, just in case.
Statism - Man's values are too selfish and hurt the "common good". Man needs a supreme authority to force people to serve the "common good" (i.e. the good of the politician's pocketbook and/or re-election). The only difference between liberals and conservatives is that they have different conceptions of this common good.
Racism and nationalism - Most people are inferior by virtue of having been born in the wrong country or with the wrong skin hue. Your own problem is significantly smaller : you're just not aware of how superior you really are. The solution is to condition yourself to see everyone as a race or a nation, and act in accordance with your status of superior being.
I'm being a little facetious, but I think you get the idea. Once people accept the idea that they are fundamentally corrupt in some way by virtue of being human, then they'll want to do the right thing, i.e. join the belief system that made them believe in this corruption, and which offers the solution. If you truly believe that man is born sinful, then you'll agree that you need to be saved. If you truly believe that man is too selfish to cooperate, then you'll naturally agree that government is needed to force people to work together.
All of these needs, of course, are completely imaginary and without foundation. That's the difference between a system based on reality and one based on fantasy. The former solves real problems based on real things. Science, for example, exists because it solves the problem of ignorance. It is a real problem with a real solution.