Rationality was born as a tool to satiate our wants and desires. Ideas, as units of rationality, are tools within the whole. Ideas are like any object. We grab ahold of those ideas that satisfy our wants and needs, and discard those that do not. When we choose to believe something, it is because it satisfies an emotional need.
I explicitly reject the notion that we can limit our beliefs to rationality. Rationality is why we choose to believe some things, but it is not how we have come to believe most things. We only stick to rationality when the subject major has no emotional incumbrances. In some areas of human though, rationality can reign, such as physics, but in economics, psychology, and sociology, emotions prevent us from more objective analysis.
The final implication is religious. I recently had an interaction with a very smart atheist friend of mine who told me that he thought that a belief in the after life was ridiculous. I got him to concede that the evidence provides no light on its existence. He asked why then I did believe, to which I replied, "Given the lack of evidence, it's the most emotionally satisfying answer." He was unsatisfied with this reponse, still wedded to rationalism. We left the discussion at that point.
I returned a few days later to continue the discussion after concluding the ideas in this series I blogged. He followed my reasoning that all beliefs are emotionally born, and that rationalism is merely a particular method of choosing beliefs. He conceded my point and admitted that my choice was justifiable. The discussion was obviously much longer, but this was the final outcome.