My problem is not so much with the existence of a God but with attributes given to God that directly contradicts observation, and I mean the problem of suffering and evil, a question nobody ever managed to resolve and is currently treated by the church as more or less an article of faith. I read most of the church fathers like Aquinas and Augustine and all of them really fail miserably to explain the existence of suffering on the divine plan. They either blame man, which is the cheapest cop-out and makes no sense (for example animals also suffer daily and terribly and they never failed to obey the divine will, not even once), or they push the matter beyond logical argument (God's mysterious ways approach). Not only that but the church literally slaughtered all early Christians that came up with good ideas to resolve the problem of sufferig and evil, like the Cathars, Pelagians, Marcionists, the lists goes on. Seriously, if you study the early church movements, later to be considered heretical, much of them are trying to explain why the world is such an unredeemable shithole while being supposedly created by and under the tutelage of an all loving all caring God. Their arguments are sound as far as religion goes, for example separating Christ and the Old Testament God (in this scenario Christ basically came to unfuck all the fucks the Old Testament God did and that's why so much of the world is fucking awful), or they place a Demiurge in between man and God, thus making God innocent, etc. The problem with those is that really makes God seem like a fucking incompetent doofus, or not as powerful, or error prone, or evil, and none of those things can be upheld along with the Johannine theory of the trinity that becames church dogma later, and also goes against catholic favorite verses about the nature of God like Psalm 18:30. Solution? Kill them all.
Of course there is no good explanation, so the only way to solve it is pushing it beyond logical discourse, pocketing the whole thing as a matter of faith, and killing everyone who disagrees with it. There has been lots of Christians groups killed over this, and I mean annihilated, by sword and fire, from existence. As Christianity developed a lot of mythology has developed to cope with this, mostly surrounding the character Satan. But then again, if you read the bible carefully Satan is not a fallen angel at all, he's just doing his job, but that's another story, if anyone is interested I can talk about it.