If someone were to ask what one thing I think would make the world a better place, I would propose the secularization of Africa and the Middle East. Which is happening, but just very slowly. Just as it happened in the Western world. Hopefully the huge free information/communication enabled by the internet will expedite it a bit.
There's a lot of disappointments that hit as one's worldview becomes less religious. A lot. I actually was just talking in the other atheism thread about the desire to 'go back'; to be religious again. Atheism is not easy on the nerves. One of the many disappointments is facing a universe that is no longer inherently just. In fact, it is not concerned with justice what so ever, and the concept of justice has no tangible consequences except for those that we create personally and as a civilization.
By our nature, when good things happen, and especially when bad things happen, we seek a reason. We seek control. We seek justice. Why are the crops bad this year? Because we didn't do our raindance right. Why did a hundred innocent children drown and/or get violently crushed in a Tsunami? Because people were behaving in a way not part of God's will. Why did I get in a random car wreck and become paraplegic? Well, that one is tough, but Everything Happens For a Reason.
So, one of the most universal experiences must also be justified: Why was this other guy able to hurt me, cheat me, manipulate me, deceive me, exploit me without consequences? Because life is a test, and he is failing, and his punishment is eternal damnation. Your reward, however, is infinite bliss. Ah, justice...it feels like an opiate.