I like to point out how unfair Hell is. If people have to burn forever because they got the wrong answer to one question (about God, Jesus etc.), what kind of monster could create a system like that?
Traditional response is that your system of morality is flawed (human morality has claimed lots of terrible things are good), and that the only true morality is God's, and Hell is actually the most just and righteous punishment befitting those who offended an infinite holiness.
Well they wouldn't know anything about my system of morality unless they asked some specifics. Their system of morality is person A and person B can commit all the same sins. If person A repents and professes the 'right beliefs', they are rewarded, while the other is punished.