Knowing that there is or isn't a God doesn't change all the heart ache, pain, trauma, and joy in one's life.

Beliefs inform attitudes and actions. And politics...

Having realized that my former religious views were mistaken, I'm glad that I don't still hold them. As others have said, I want to believe as many true things and as few false things as possible. And I'm not content to sit idly by without at least exposing some others to some alternate points of view.

Why were you angry in stage 1? For no good reason, so you just brushed it off? No, I think you were angry for good reason, and I suspect you'd agree. You probably have at least some level of understanding of the harms that religion and magical thinking can cause. That doesn't mean that those who misled+ you were intentionally deceitful, nor that it's good or helpful for you to stay angry. But it does challenge the notion that you should leave the believers alone, so that they can propagate their religion without opposition.

We don't live in a vacuum, you know?

Not sure how well I've expressed myself here, but hopefully you see at least some of what I'm saying.

• Notice, I didn't say you were "lied" to. That speaks to intent.

Pretty much the same for me. I've lost/not gained friends I otherwise would have been friendly to if not for my atheism and their religion. Nowadays, I don't talk about that. Ignorance is bliss, particularly for the ignorant. Just because they're ignorant about this topic though, doesn't mean they're all that bad. And they don't listen anyway.

I think as I gradually grew up, I let go of Santa, the Easter Bunny, God... It wasn't a fixed line I had to cross. I think my agnostic years were early on; my teens maybe? And my atheism was a natural step. I was a live and let live person for a long, long time.
It's only recently that I've become more militant or outspoken, though I still respect other's rights to believe what they want.
I think it might be because I'm more comfortable with who I am.

I was very angry and confrontational after I realized I was an atheist. This phase lasted for about two years. I'm glad I'm more mellow right now. Also what you described at the end sounds like Apatheism, you can look into it if you want to.