If you really want to blow a JWs mind, get into a discusion about free will in the new world, (after the 1000 years is over).
Ask them what will happen when people sin (like Adam and Eve did) after a few million years. They will initially give you a "does not compute" look but if you have a bit of patience they don't like it at all. It basially means people are going to be executed in the new system if they violate the rules, just like Adam and Eve.
And they know it will happen so it caused the hamster wheel to start spinning.
I asked a JW relative of mine that same question. She said they would instantly be put to death. I said, but I thought Relelation 21 said that "death will be no more." She said that's a different kind of death. I said how so? She said the type of death that will be no more is death resulting from sin. I was like, but my question was what happens when someone decides to sin in the New System. They do have free will don't they? They could choose to sin if they want. She was like, I meant Adamic death. In other words, inherited sin.
It went on and on and i could never get anywhere with her.