The original sin, never identified by any religion and yet oft-mentioned indirectly by ancient civilizations through their own recalling of Paradise lost, is a very real thing.
It is the presence of concept in man's mind.
This might seem absolutely impossible as, most will say, mind *IS* concept. It is not. Concepts are a travesty of reality. They are a simple symbolic representation thereof, but not absolutely equivalent to reality. Only reality itself is equivalent to reality. What the current, false evolution of man's mind is trying to accomplish is the representation of the whole of reality through use of symbols that have non-absolute meaning. This creates a situation where the complexity of the task is orders of magnitude greater than infinity. It is not doable. Thus is man's mind's so-called evolution doomed to fail.
Mind can connect with actual, objective, Absolute reality just fine. Concepts were first presented to man as a shortcut to his mental evolution. It was seen that concepts, because they can so easily be created and destroyed, could be used to this end, and that later on, man could simply "de-invert" his mind, sort of "turning around" his mind's eye from concepts to Reality. It wasn't obvious at first that concepts would create a huge chain reaction of memory loading, and quickly fog up man's mind enough that the extremely simple "de-invertion" would become impossible to understand for someone hypnotized into concepts and beliefs. Such is the case today. Mind de-invertion is not easy for anyone.
Interestingly, the realization of this inevitable, total failure of the human mind's inverted evolutive progress is key to the realization that the increasingly complex thoughts of the modern intellect can eventually become the limiting factor in the very process of said false evolution, which I will further refer to as "involution". This means that as man's intellect grows better, stronger, more complex and subtle at the same time, this realization eventually dawns in him. So the very process of this false evolution is a negative paradox, one that destroys itself... in some cases. In many cases, the power of concepts over the mind is too strong for an awakening to the absurdity of this paradox to happen.
This means that some people will get this and others, not. Sadly, it isn't a question of quality of person, but more of psychological structure. Concepts are symbols that represent reality but aren't reality. Their value is derived from subjective observation and is truncated where the observer's mind's eye does not see. As man only sees the part of any object facing him, so it is with every situation he ever meets. His observation is thus incomplete and the memory he keeps of it, useless.
That is why no matter how much "thinking" about situations is done, things happen differently. 99.99% of the time. Because there are too many factors involved. Representing each of these factors with concepts is not doable because they would need to be observed in the first place. For such observations to happen in a thorough manner, personal experience would need to be infinite. It cannot be.
In essence, the "defilements" are concepts. Discernment is a true mind ability, one that is born when the link between man's mind and objective reality is strong enough. For that to happen, the concepts must first be destroyed. In essence, I agree with the ancient texts but one could never have gotten to the conclusion that concepts are the defilements without first having some discernment. That's why it takes so long for man to grow beyond his simple animalistic psychology.