Caution, the following may seem a little disorganized. It was written in a state of flow, and not thought out and organized beforehand (I hate writing like that, blah).
It is in my opinion that atheists are wrong in their certainty of an unknown. I used to be an atheist, but I found the position ironically requires faith to maintain (and a belief in an all-knowing, all-aware self). It's without question that this universe is a complex thing, and to make matters worse the ability to be aware of the self is another one of those big unknowns. It's a shame that atheists close themselves off to certain spiritual experiences. It's fairly easy to experience the presence with an open heart (love being what opens it). The reason I consider myself to be an 'agnostic' is because I am ignorant of the underlying source of it. Of course I have no way of knowing that such a thing is capable of creating a universe and/or able listen to and answer prayers. But I definitely see how the "higher power" can be a source of strength for people, regardless of what it is. Without a doubt it does exist on some level (even if it is only in the mind). So yeah, atheism is not a good position to take. I find that most atheists (especially the outspoken ones) are those that have felt pain as a result of religion (obviously not from God, which is not a painful experience). It's easy to attack religion (which I have done a lot of in the past), but when it comes to God, it's one of those things that need to be experienced. It's outside of our external senses, so we have a tough time describing it. In fact, the only word that comes even close to describing it is 'love'. Many people in today's society are afraid of love, and this is why they have trouble with relationships in general, it is why the rate of depression and other mental disorders are on the rise (depression is a spiritual illness because its source is the core of our being in the same way that love is). The word 'love' has been labeled as being cliche and corny in society, and we wonder why society is suffering today.
1 John 4:8 is a bible verse that, I believe, gets at the heart of all of this.
"Whoever does not love does not know God, for God is love"
If God is love, then it's hard to deny that God cannot be experienced. So essentially atheists don't believe love exists.