Human beings, we are told, are weak and sinful. In their flesh and desires, if left uncontrolled and molded by religious and other institutions, would bring horrible consequences. Just how true this may be is a matter of debate. Regardless of the extent of natural human debauchery, when looking at a newborn baby, you have to wonder why it would be created flawed or have sin. In addition, why would a god would create people in one way, but commanded them to act in another?
A newborn baby can be one of the most beautiful things imaginable to people (unless it was unfortunate to be born horribly deformed). However, even a newborn baby is said to be stained with original sin. It seems beyond comprehension that a being so pure and innocent could be stained in any way for something a very distant ancestor did.
In Christianity, this guilt is further compounded by other ancestors killing of the creator’s son (as part of his plan) long ago.
Furthermore, the soul is said to be weak. While human beings certainly have weaknesses, and they are easy to see, it is hard to imagine why these weaknesses would have been created by a designer. Would not a god be able to design people with fewer flaws? Why not make them much stronger and good at heart? People are born with desires but little natural incentives to be good. Society must teach those. It seems that people could have been made with better motives at heart without losing free will. For example, feelings of empathy (that vary with the individual) can help people act more kindly towards one another. Why weren’t they made stronger? Further complicating this picture, science now shows that damage to the brain leaves some people physically unable to even feel empathy.
Furthermore, many natural instincts people are born with run totally contrary to what religion teaches. The most obvious example of this is sexual desire (see: god and sex). If people are to live monogamous lives, why are they not designed to be more satisfied with monogamous relationships (as some, but not all animals are)? Since most people really want to stay loyal to their partners, why not allow them to turn off that harmful desire to sleep around?
While people can certainly derive a lot of pleasure from sex, the amount of pain, frustration, and supposedly damned souls, this overly-intense sex drive has caused, makes it much more of a burden to humanity than a gift. Why would not a creator design people in a way that made it easier, and not more difficult, for them to follow his commands?
Then, there are the most clearly harmful desires in people. For example, excessive greed, pride, the ability to see outsiders as less human, etc. have all led to many problems in human history. While it may be too much to expect human beings to have been designed with the hearts of angels (assuming they exist of course), why not with at least better hearts closer to the ideals?
Human beings are expected to not only overcome the flaws in their imperfect design, but follow rules and live to standards that are virtually impossible to meet. As bad as this sounds, it is made worse by the stakes of the game. For what their flawed flesh does and their imperfect minds think, their immortal souls can be tortured for all eternity according to religious doctrine. With the stakes so high and the fate so horrible, would not any merciful, just designer have made people as strong and perfect as possible to increase, rather than decrease, the chances of them passing this test?
While how good or bad human nature is can be debated, one thing is for sure, people could have been made a lot better. In addition, many of the ideals that religion calls for do not mesh well with human nature. How could the creator of both have been so contradictory? As it stands, according to the Abrahamic religions, people are created sick and ordered to be well. It is impossible to see the rationality of this, especially if the creator behind all this is fair, moral and just.