Disclaimer. This is just my personal experience, and not meant to judge anyone else.
The biggest thing I was ever “wrong” about, was my former religion. I was raised a Baptist. Sunday school, and all.
In my teens, I was pretty sure that my religion was wrong. I still talked, and prayed to my God frequently though. I no longer went to church, and I suppose I was becoming an agnostic.
As I learned more about the world, and science, I started drifting further towards atheism.
By my mid twenties, I was almost a full atheist. I worked in emergency medicine, at the time. I witnessed indescribably terrible things. I decided after some time, that there was no possibility of a “loving” God. Or that he/she/it either hated all life, maybe was sadistic even, or was perhaps just powerless and more of an observer.
At this point, I am an atheist.
It took many years to let go of any form of a deity. It took lots of soul searching, and introspection. It was scary. I didn’t want to feel that this “god” was no longer protecting me. This “god,” I had probably talked to, more than any person.
As my belief in that God faded, many of my other beliefs unraveled as well. I had to reexamine every belief I ever had. I turned them all around, and looked from every angle. It was a big change, or series of changes. I wanted to believe. That was the ultimate conclusion that I had to accept. Many of my fears drove me to exclude sense, and reason from the things I believed.
At first, I felt scared, and very alone. I no longer had that someone to talk to, or seek counsel from. I didn’t make deals with God anymore, or pray for anything. And death became WAY scarier. Still is…
Eventually, I felt more confident though. I realized that I did have some beliefs. I believed in science and most importantly, I believed in myself. I felt like a man who had walked on crutches my whole life, and then had the power to cast them away. When I would get into a bad situation, I didn’t have anyone looking out for me. I was alone. But I learned to be capable. I learned to be innovative, and resourceful. I learned more about self defense. I learned to trust my instincts. I learned about how deceptive, and manipulative people are.
I learned to respect all life. I no longer saw the trees and the grass as a backdrop from my god. I saw each thing, as an individual. Each star. Each planet. The universe became far more interesting.
I’m not trying to get anyone to look at their faith. I’m just explaining what was a really big deal,to me, to be wrong about.
I’ve also learned a LOT here. I have a deep value of this place.