Alas, the only over-inflation of abilities around here comes from the likes of the egregious Burns (for example) and his one-man mission to get people to believe in his god via his stunning arsenal of howling logical fallacies.
This is after all a man who claims absolute certainty.
If I had an over-inflated sense of my abilities I would consider him capable of rational thought and able to advance a non-fallacious argument for us to take seriously. He clearly isn't.
Can't say I have read through the whole Searching for God thread - it is very long- but maybe AB chooses absolute certainty because it work for him - it increases his happiness or subjective well-being. And so he offers it to anyone who wants to give it a try because he thinks it will increase their happiness.
Not sure how your abilities would make AB capabale of rational thought about religion - it depends which meaning of rational you are using - according to economists pursuing a course of action that you think serves your best interests is rational. Alternatively pursuing a course of action that you think is in the best interests of others is also rational.
A happiness research paper on this could answer some questions relating to Sriram's bafflement about the choices people make. It distinguishes between well being (satisfaction of the individual's preferences based on what rational, self-interested, well-informed people would generally prefer) and subjective well-being (SWB). The paper looks at different possible definitions of the concept of well-being: (1)objective-list accounts of well-being, (2)preferentialist accounts (satisfaction of personal preferences = well-being), and (3)mental state accounts (either achieving more pleasure than pain OR a broader definition is achieving your preferred mental state).
http://www.ericposner.com/posner_happiness_cba