What's the worst argument for Christianity that you've heard?

The one I hate most is the argument used all the time by William Lane Craig, I may have misspelled his name but I don't care to look him up or to get the name of the argument. It boils down to you exist therefore God. It's overused and a pathetically weak argument for God but I guess it'll have to make due until mankind finds the first falsifiable observation that indicate an actual God, we've been looking since we became human and haven't found one yet. I'm certainly not holding my breath, if it happens it'll happen when and if God decides to let us know if her existence wasn't purely imaginary.

Jehovah witnesses claiming to be the ONLY TRUE  CHRISTIANS on the planet!

That's a difficult question considering they are all horrible arguments. One is pointing at natural formations and claiming they are intelligent creations with no good reasons to back that up and plenty to back up natural formations. Another is out of our ignorance, where not knowing the answer means we should insert their God of choice as a place filler, where magical fairies could work equally as well. Those are poor arguments for God, but you asked about Christianity specifically where I find it belittling to any God to think it needs something, such as a Son to sacrifice to Himself for the rules He supposedly put in place. There is no "reasonable" need for Jesus if you are thinking at a higher intelligence level. The concept is equivalent to having two children, where one is too young to know better but the other is old enough to know better, so you sacrifice/punish the older child because the other child is too young to comprehend. That is not how rational people operate, you show compassion for the fact that the younger child is too young to comprehend so you don't punish a child for being a child, you attempt to keep harm and havoc out of that child's way, where if you leave a cup of milk out and the young child knocks it over, it's not the child's fault, it's the parents fault for not seeing that accident happening considering the child cannot yet comprehend. This leads to a slew of poor excuses by Christians as to why Jesus is needed and it seems to take the light off the Father who now sits in the back seat to Jesus vs. other religions that literally have one God and no three in one Gods.

For me, it's the appeal to ignorance: "If God isn't real, how do you explain _________?" This is an argument that Christianity shares with every other religion ever created, which is a problem in itself.

The answer to anything unknown is "I don't know," not "God did it." Pointing out that there are gaps in human knowledge is no more effective at showing the existence of deities than it is at showing the existence of the Tooth Fairy.

Probably Pascal's Wager, because it assumes that people can completely kid themselves they believe in something they don't and that even God would be taken in by that.

Every word & page in the bible.

The Bible itself is the worst argument, it is so confused and clearly written by several different people with differing views on the subject who never collaborated to make a united doctrine. I feel bad that they're stuck with such a disjointed and inconsistent mess.

People today or even in 400 AD were making better arguments for Christianity than the biblical authors did. It's a shame they're stuck with what they have written in stone.

The assertion that God exists.                           

Pascal's Wager is pretty damn bad. As is any argument from ignorance. Like: "we can't explain this..? Therefore MY god must have done it!!" *Face-palms.*

Also, one thing I especially dislike, speaking as a non-Christian, rather anti-Abrahamic spiritual person..? Is this whole arrogant assumption, by so many Christians, that if we're talking about the prospect of *A* god? Or some kind of divine force, more generally speaking? It has to automatically be theirs! Namely, Yahweh! Or what they personally associate with that concept.. Which makes me want to puke! Because I think their version of it f*cking SUCKS! And yet I'm SO not an atheist, either! But yeah.. I'm just tired of seeing them corrupt, subvert and exploit something that, at least in my experience, can actually be something SO extremely beautiful and sacred! By pretending they have some kind of monopoly on it! And by infesting the mere concept of spirituality, or divinity, itself, with their yucky-as-sh*t, oppressive Christian notions of everything! Which.. I was personally harmed by that. And I'm sure many other people have been, too. Spiritually inclined people, who decide they want F*CK-ALL to do with Christianity, but have still been tricked by the prevailing social narrative, (perpetuated by Christians, mainly), to think atheist materialism is their only other option, then.

The argument about the authenticity of the Holy Bible itself.