One thing I noticed in myself when I went from being a Christian in the first twelve years of my life, then an agnostic for three years, then finally an atheist, was the censorship of thought.
I used to be worried that the things I was thinking about were bad, that passively churning through my own mind was something of which to be careful. But when I became an atheist I felt my brain was mine alone and now that feeling of privacy within myself is something very important to me.
I would have lost out on this if I had continued to be a Christian.
My time in the church did manage to lead me to uncover what seemed to be a minority, a group that went beyond the orthodoxy and wasn't using religion in their lives as the "thought police" or "moral conformance squad."
The bulk, however, was intrusive, and I got screwed up nicely in SOME ways (usually involving how others viewed me).
Author M. Scott Peck referred to one system of spiritual growth he had perceived:
1. Unbeliever
2. Conformer.
3. Challenger
4. Mystic
While you'll probably bristle at it by having agnostics/atheists listed at Stage 3 (and you don't have to accept this framework, obviously -- it was Peck's idea or he got it from elsewhere), my point really is that Stage #2 is where many people end up and stay.
Especially the ones who start at stage #1, so Stage #2 is actually beneficial for them. "Jesus turned my life around!" they will claim... and truthfully. Because religion DID shape them up and help them get over some big issues in their lives, it brought them some desperately needed structure and meaning that they were not finding (nor would have found) on their own. And many people leap right into Stage #2 and never really go through a Stage #1.
But God at Stage #2 is still sort of a traffic cop figure, and that's where many religions people stick, and anyone who moves ahead to an agnostic/atheist or (ironically) a mystic position will be cast out as backsliding rather than being seen as advancing. Anyone in the faith I've found worth being vulnerable to has not really been in Stage #2, but it's just a small minority.
Ahh, this is why it is important. You can be an agnostic theist. That is, agnostic does not mean you do not believe. It's a theory of knowledge. It's actually pretty common even though most don't realize it. Most of the times when "faith" is used as a foundation for belief, the person is an agnostic theist.
That's why I often call myself a Christian agnostic. I have inclinations that lead me to articulate life through a Christianized lens, but my foundational assumption is that I cannot know anything for certain, so anything I hold beyond the observable is pure faith. (Whereas many Christian-professing people actually don't operate on faith, they turn their unprovable religion into "fact" somehow and then try to believe it in as such and speak of it as if every detail is 100% true, which I find presumptuous and muddying down what can truly be known and shown versus merely believed in.)