That's basically Pascal's Wager argument. It's been debunked a lot of ways if you look it up. The short answer is 1) that the chances that any particular faith are wrong are just as good or worse than no faith. You believe in Christ? What if Krishna's the real deal? and 2) It's just too obvious that faith is a human construct, because of the variety and traceable sources, meaning the weight of probability is on non-faith.

"If your god is real, and that's a mighty big IF, I'd spit in it's eye and give it an earful about what a complete fucking passive/aggressive, absentee-father, misogynistic douchebag, with anger issues, it is. Then, I'd probably take a really big swing at it's face."

Might throw in a few extra "fuck yous", too.

Something along the lines of well, if you're wrong instead of me, how much of your limited time here did you waste on stupid shit?

First of all, is that a question you're asking yourself? Because if you were, you wouldn't be so determined to sway my viewpoint. It's their insecurity that prompts this question.

For me it's not about being right or wrong. It's about doing the best with what I've got. If I'm wrong, and God is love, then we will work something out. The most loving thing would be reincarnation. That would be like a time-out, where I get to try again and get it right. If I'm wrong, and God is not loving, then I don't want to be anywhere near him as heaven would resemble North Korea and eternity with that would be unbearable. But there would be no escape.

Meanwhile, it's not life after death that compels me, it's life after birth.

Then my 'error' allowed me to live a healthier, happier life, rather than having an irrational fear rule over me.

At least I'll be wrong for all the right reasons.

If they are Christian I would say "What if you are wrong about Islam?"
or
"I don't go to church 'just in case' God is real for the same reason I don't put garlic around incase vampires are real."

Both stolen from Facebook memes but I like them.

My reply would be "so what?"

When I see this question I have to assume that those who ask it must, at least in some small measure, still find the idea of a literal god to be a believable concept.
My response is that the more one studies science in general, and evolution in particular, and psychology, anthropology, and history, as well as critical thinking, etc., the less believable such an idea becomes. And when the notion finally becomes completely untenable to the informed mind, that question evaporates from the pool of concerns.

Oh fucking well.

Maybe I am. This could be the case, and I don't lose sight of that. But, I can say with certainty, if a god should exist it isn't yours.

Bitch.

I would ask them what if they were wrong about Mohamed or Buddha or Thor or any number of gods they don't believe in? It's not too hard when you realize they are trying to turn it into a black and white issue when really they are failing to see all the shades of gray that don't fit their narrative.

Then I'm wrong.

It's my choice.

As noted below, it's as in Pascal's Wager. Personally I feel the evidence is very clear and I'd much prefer to spend my only pass through here on myself and others like me rather than waste it on an imaginary sky fairy.

I'll let Stephen Fry answer the question:

My first response would be, "Like Duh! What the fuck does it matter now?"

Pascal's wager is total stupidity. How is it an all knowing critter would not know one of their minions what attempting to game the system. Just pure mental illness.

Does not matter. I have lived a good life, been as fair and compassionate as I felt was warranted with what I knew and was capable of at the time.

If there is a god - and it's not the one I learned about as a child - then I would adapt to that reality.

If there is a god - and it IS the one I learned about as a child - well then he failed at convincing me - so what kind of god is that?

That’s just referring to Pascal’s Wager. For me if I’m wrong, so what. I’ve been wrong before. Not bowing to no one! As the saying goes, can’t remember who to quote, I think it may have been the Mexican revolutionary Zapata, “Better to die on your feet than live in your knees”

if i am wrong -- which i feel so certain i am not that this is merely a thought exercise, not a plan -- consider the following:

1. if there is a god (singular) and it's a good god, it doesn't care whether i believed in it.

2. if there is a bad god i'm screwed anyway because a bad god is going to enjoy punishing me whether or not i've misbehaved, and not everyone agrees on what is good or bad behavior anyway.

3. if there is a heaven and all good people go there and we meet all our loved ones again, what if someone loves you but you don't love that person; are you then stalked for eternity? and who chooses the music and the menu? if it's not me, i don't want to go.

g

I'm a good person. In my humble opinion, I'm a much nicer person than most christians I know. So, if there is actually a loving god, I believe he would judge me on how I've lived my life. And if he would judge me for not believing in him, then so be it. Who would want to hang out in heaven with a bunch of self righteous assholes anyway.

"What if you're wrong?"
"Well, simple, really. If there is a god, of any kind, and if he/she/it is so malevolent as to want to punish me for not believing something that has zero data to back it up, creation myths that change as needed,

It is not so much a matter of being wrong....it is a matter of what is the true story.... my bet is "god" is an atheist .....

My reply: "I rather be wrong than worship your god".

We have to go with our best reasoning and intuition. Of what value is a declaration of belief if made under threat of hell?