My friend got sucked into it because of a girl. His parents weren't religious. I don't think he had gone to church more than twice in his life by high school, and he, just like the rest of us, trash talked our school's requirements to have a 'chapel' hour once a week. He was as blasé as they come about religion, perhaps an agnostic in the christian hemisphere at best, but when he started dating a christian girl, he went to church with her, made friends with her friends at church, etc. Now 15 years later he's indoctrinating his kids with her, and a deacon at his church. The power of social influence is enormous. I can't imagine how difficult it must be to break free, or even just consider information that is contradictory, if you have the combination of early influence and the later social influence from family, friends, and the wider social circle that is part and parcel of a church.