Oh, and in terms of preventing people from making otherwise logical decisions, if you are speaking of when systems of nebulous belief - such as a religion forbidding a rape victim from getting an abortion (obviously extreme example) - I agree that it gets in the way. But a concern for one's own consideration of what is a good code of conduct - not a church's, or culture's, but a logical look at what you deem important and 'good' - that can assist in making logical decisions that take into account the fact that you are human and much more complex than a computer.
Also, wouldn't it depend on what type of rationality or philosophy of thought you are coming from? I don't even know the deeper topics of philosophy in regards to the human mind, but aren't there libraries of material on the subject of what motivates humans and how to approach logic itself?
Edit: For some reason it didn't show up when I refreshed, so I reposted... then it became a double post. Had to delete the first one.