First off I want to tell you where I come from... Im an Atheist, I have been an Atheist since Im 13 years old.
Being an Atheist is not being part of a community, is something you decide alone and continue the "journey" alone. It is label that you put on yourself that states: "I dont believe in God/Gods.". That statement is the only thing all atheists have in comon. Some atheists believe in all other sort of things, others dont... again, the only thing that defines Atheism is the lack of belief in God or Gods.

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So what do I believe in?

I believe in people. I believe in you. I believe if I had a Ferrari and went to you at a bar and said "hey, my wife is having a baby, I have to go to the hospital, here are the keys PLEASE park my car cause I have to go!"... you wouldnt steal the car. You would park it, you would probably get nervous "OMG Ok I never drove this thing fuck... no problem GO!".
I belive most people are good and just want to help. And that to me is the most spiritual thing about the universe.