In my search for a belief system, I seek truth, not happiness. Believing in something pleasant would bring me no happiness if I had any doubts as to its validity. I have no doubt about the lack of a higher being. Here's why:
It is physically impossible for there to have been a beginning of time. One of the primary rules of physics is that matter cannot be created or destroyed. Therefor there cannot ever have been a time when there was nothing in the universe. Theists will argue that God doesn't have to follow the rules of physics, and that brings me to my second point.
If you are a theist, you believe that God created the universe and that God has always existed, and will always exist. If you are an atheist, you probably believe that the universe has always and will always exist. Eithor way, you believe that something has existed for an infinite amount of time. We know that the universe does exist now, but we don't know if God exists now. So therefor it is more likely that the universe has always existed than it is that God has always existed, or even does today.
Also consider this: if there was no God, there would be no purpose for life. If there was no God, life would not be fair. Life has no purpose. Life is not fair. So, the only reason to believe in God is because you want to. Many people will disagree with me here and say that life has a purpose, they just haven't figured out what it is yet, and that life is fair and people always get what's coming to them. This simply isn't true, and I think deep down inside you know that. It's just more comfortable to think those kinds of things. They're not true, but people believe them because they want to.
Fourth, I fail to see how anyone can in good conscience dismiss the theory of evolution in favor of creationism. There is overwhelming evidence for evolution, and none at all for creationism. People refuse to believe that we humans are no better than the apes. It gives people a sense of justification to think that we are somehow "better" than the animals with which we share the planet. It is pure stubborn arrogance that prevents them from looking at the facts in an objective manner. Our instincts to eat, seek shelter, and procreate coincide with natural selection, and explain why our race has survived the millennia. However, from the christian point of view, our instinct to procreate goes directly against the rules set out for us by God.
Also, God gave us free will, but those who accept without questioning will be more readily accepted into heaven. Why would God give us the ability to reason and then expect us to take anything on faith?
So, there are many questions which cannot be answered by religion without making an effort to interpret the word in such a way that it coincides with what we instinctively know to be true. Why should you have to make an effort to believe in something? The truth is self-evident. The only reason to belive in God is because you want to. Let me say that again. The only reason to believe in God is because you want to.
Now that I have established my position, allow me to explain how this has influenced my view of life. First of all, atheists do NOT take their religion lightly. I know that if some people are right, I'm damned. It takes quite a commitment to face that threat without fear. A lot of people believe in God "just to be on the safe side". Well if you're one of those people you're just as damned as I am because you don't really believe. You have to make a decision and really stick to it, not just pay lip service to the church in exchange for admittance into heaven. Some theists view atheists as lazy, becuase we don't put forth an effort to believe. I contend that one should be forced by logic to believe in the truth, because it is self-evident. No effort is required beyond gathering facts and asessing their value.