Atheist to Catholic convert: How nice for you. Since you’re a Catholic you don’t have to think about the meaning of life. Just believe whatever the Pope tells you.
Catholic convert to Atheist: How nice for you. Since you’re an atheist you don’t have to think about the meaning of life since for you there is no meaning to life.
Atheist: Your religion, with it’s Sugar Daddy in the sky who gives you eternal life is just wishful thinking for weaklings who are afraid of the dark. You’re just lying to yourself.
Catholic: My Heavenly Father is also my eternal judge. I will have to answer for all my choices and take responsibility for all my actions. I therefore might go to hell, not heaven. If I were thinking wishfully this is not what I would have wished for, and if the darkness of hell is eternal, don’t you think we should be afraid of it?
Atheist: I’m not afraid of the dark.
Catholic: Now who’s lying to himself?