Absolutely...which is why I see morality as a mask we put on our true selves. Moral action can be antithetical to individual survival but helps society as a whole function. Moral systems are thus imposed upon us and I think may contribute to aberant behaviors. Take, for instance, age of consent laws. By nature, humans are prepared to procreate at a certain age...anywhere from 11 on lets say. So the urges to procreate are there by natural progression. Yet we, and not even all that long ago, have suppressed the urges by making moral and legal rules against underage sex. Does this lead to suppressed instincts and does this have any effect on the emotional state of people? I do not have the answers, but I think about this alot. Are we, by restricting human nature, causing other problems? Don't get me wrong, I understand the reasons for some restrictions.
This is just a speculation of course. Thus, I do not think that Situations or Institutions transform 'good' people into 'bad' people, but rather gives us the opportunity to remove our moral mask and lets the dark side come out occasionally. I do not believe that we are inhernetly evil, or immoral, or inherently good, or moral. We are both...and we show both based on the situation we are involved in. I do tend to think that without constant reflection and diligence, we would gravitate toward a less than 'moral' state.