I've gone from Sunday attending to more lax and agnostic. Does that count? If so, is because of how inconsistent the actual practical actions of churches I've been to. Started protestant, but enough were hypocrites (remind me of the pharisees) so I stopped going. Became catholic and loved it, but the way the church has continually terribly handled the sex abuse pedo cases has disgusted me. Priests should be held to a higher standard, not lower.
Additionally, I don't wanna be associated with the people who are Christian on TV. All the right wing Republicans in the US govt are terrible people. Whatever they say they are, I don't wanna be a part of that. It's hard to reconcile "love your neighbor" and then legislate their live away or give crazy people unfettered access to guns.
On a more practical level, I like a lot of the charity work and compassion taught by Jesus. I'm OK with the spiritual aspects. I cannot get behind the church's message (mostly protestant) about personal relationship with God. If God intervenes, then that means it's his responsibility when he doesn't intervene and a lot of terrible things are his fault. If he doesn't intervene, then a lot of what the church says is wrong. It doesn't add up.