I have been told that a great justification for religion is that it makes people happy. I won't dispute that plenty of people are happier with religion. I have been fairly happy with religion, myself, although not consistently.
When expressing my doubts to my father, he appealed to my love for my wife, and basically told me that if I want to be with her forever, just think about that and I'll know what the truth is.
The best I can boil his argument down to is "if you want something bad enough, it must be true."
Now, don't get me wrong, I'd do anything to be able to remain with my wife, she is my one joy. But I just can't believe that wishing hard enough is every going to make something true.
I once told my wife that I would rather be right than happy. By this, I mean that I would rather search after the truth than ignore the question because denial would make me happier. I don't think most people would say the same, based on the unwillingness of many to question their beliefs. I can't fault them for this; happiness is certainly nice, and there is no rational reason for me to be obsessed with the reality of things.
However, I also contend that there is no particularly rational reason to prefer happiness, either. When others tell me that it is worth believing in god in order to be happy, I just can't accept it. For them, sure, great, but not for me. I want to know things. I don't think I can be happy while in denial of the fact that I am ignoring possible damning arguments against my beliefs and possible routes to truth.
When I present this argument to my theistic friends, I am often told (in an annoyed voice), "well, if you are unwilling to have faith, you can't know anything for sure." And I always agree wholeheartedly! But how could I ever be satisfied with just guessing what the truth is? And what do we have except reason besides an arbitrary guess?
What surprises me is the complete willingness for theists to voluntarily admit to epistemological nihilism. I guess it is just that they value happiness above truth, which, like I said, is fine.
There is a surprising honesty in this, actually. When pressed, most of my theist friends will admit to not being able to know, but express their choice to make happiness a priority, and not necessarily logic.
I don't need to convince anyone of the falsehood of their beliefs, and indeed, that is not the purpose of this blog (which no one reads anyway). I just want to be allowed my own priorities, which happen to tend toward a rational search for truth.