Critical? They do? Like what?
Anything about human nature that is not
stone obvious?
As for god, teaching about a non existent
psycho monster does not seem so good.
Some people believe that we are basically good. Genesis 2-3 teaches us that we have a flaw in our nature. We Jews say that we have a Yetzer HaTov, an inclination for good (which comes from being created in the image of God) and a Yetzer HaRa, an inclination for evil. Of course different Jews take Genesis as literal, allegorical, or figuratively depending on whom you ask. Here is my take.
There was a time in our evolution when we were still morally unconscious. By that I mean we may still have had rudimentary senses of justice and empathy, such as chimps have today. But that self reflection that comes where we know something is wrong because we can put ourselves in another's shoes, and the feelings of guilt that comes when we do it anyways was simply not evolved yet.
In this state we were as very, very young children, not really morally responsible for the things we did. Indeed, more akin to the other animals. Can we blame a cat for playing with its prey? It is functioning on its instincts alone. And so we were blissfully unaware, without the angst of conscience. We were still 100% part of nature. We were in harmony with ourselves, with nature, and with God.
There had to have been a first occasion, and a first person, when this happened. And it was adaptive. Biologically it spread. But there was a cost. It created a cataclysmic chasm between our instincts and our conscience. Forever on since that moment there would be occasions when our conscience and our instincts would be at odds. To start with, this meant that we would no longer be in harmony with ourselves. It also meant that we were no longer 100% in harmony with nature. It meant that we were not in harmony with others. And of course, it meant we were no longer in harmony with God.
You might say that this moment where we came into moral sentience could figuratively be called the moment when we "ate of the tree of the knowledge of Good and Evil." And this movement into a state of disharmony would be what Christians call "The Fall." Certainly, the fact that our instincts NOW cause problems for our higher level conscience means that our instincts are a lower level "Yetzer HaRa."
Unlike Christianity, Judaism teaches that God has given mankind a healthy balance of Yetzer HaRa and Yetzer HaTov. The idea is not to get rid of Yetzer HaRa, but to subjugate it through sanctifying it--use our instincts in the right way, the right time, with the right person, for the right reason, in the right place, the right way, etc. For example, we have an instinct to procreate -- do so within the committed stable relationship of a marriage between a man and a woman.
Indeed, the world would be a terrible place if our Yetzer HaRa were to disappear. We are talking about really basic instincts such as sex, acquisition, competition, and anger. If we stop to think about it, although these can lead to some pretty ugly stuff, they are also the building blocks of basic society -- procreation, business, government... So the ideal becomes taming the instincts with one's conscience rather than eradicating it.