An emotional argument for atheism? Challenge a believer to consider Abraham's agreement to slaughter his son Isaac like an animal, and ask a believer how they relate the story to their personal life.

By the way, I reject the term sacrifice, because a sacrifice is a tradeoff, where we give up something personally to gain a greater good. Abraham's agreement to slaughter his son Isaac serves no greater good -- it's a lose-lose proposition. It's like when Gary Shandling made love with his girlfriend and he asked, "Was it good for you?" and she replied, "Gary -- I don't think this is good for anybody."

So you can ask a believer on two levels: 1) Do you agree Abraham did the right thing in agreeing to murder his son? (and are you "good enough" to agree to murder your children, too?) and 2) Do you agree Abraham's god did a good thing by giving Abraham a lose-lose proposition as a test?

Some percentage of believers investigate atheism because they realize this emotional and moral horror -- not because they value a logically self-consistent system of knowledge per se.