I'd been an atheist since 14 and have spent the majority of my life an atheist. I believed that there was insufficient evidence for the existence of God.
In many ways I still believe that. I dont believe in a magic transdimensional entity most people believe in when they talk about God.
However, much like you feel the spirit of celebration when your team scores a goal, or the spirit of accomplishment when you complete a difficult task, or the spirit of Ares when your kid dumps a cup of water on your computer and laughs in your face, God is the spirit of knowing the right thing to do.
God is, at least, a very real force that exists, in part, within us all in Western culture. We've inherited God. That's my conclusion anyway.
To be clear, I'm Christian now, as of August. I take the Bible seriously now. But to be extra clear, I believe it's all metaphor. Metaphor that tells you deep truths about yourself.
For those interested, the catalyst for me was Jordan Peterson's series "The Psychological Significance of the Biblical Stories", available in full for free on YouTube