I have yet to see concrete evidence of the existence of God. And I believe I may be able to prove there is no God. Feel free to tell me if my logic is flawed.
If God exists he is: all knowing, all loving, all powerful. Which means: he knows everything, loves everyone and cares about everything, and can do anything even beyond what our imaginations can comprehend. He should know then, that I am an Atheist. I deny his existence based on lack of evidence. He should also know that showing me proof of his existence would effectively end my denial. So, I call on Him now to show himself, or some proof of His existence. ............ And, to clarify, having a human being speak for you does not qualify, because second hand knowledge is never acceptable whether it be in science, philosophy, or life. .............. If God loved and cared for everyone then I see no reason for him to hide himself from anyone. He should care about the way we all live our lives. If he really cares about how I live my life or what I chose to do or think he would interfere and prove himself. He can do anything to prove himself, so why doesn't he. Without prove of his existence then I cannot know that he loves me and may assume that he does not. Then he is not all loving, he is not God, and does not exist.