I was having lunch with a brilliant friend who also happens to be a wonderful storyteller. He is a philosopher and a lawyer and a Catholic.
What, he asked me, is the question I would least like to hear from God when he asks why I should be admitted to heaven?
My mind start racing – “What did you do for the poor?” “Why did you spend so much on Apple products?” “Why did you talk better than you lived?” There were just so many of them.
“Wanna know what mine is?” he asked.

Of course, I said.
He paused.
“Ok, so I get to heaven and God says, ‘I have one question for you. Suppose a train is leaving San Francisco at 70 MPH and another is leaving….”
That is actually a most terrifying question. Does anyone like those questions?
ADDITION: What is your horror question (in the spirit of the train question)? Mine might actually be, “Hey, remember all those years of Chinese you took? Say, ‘Please let me into heaven and you are in.'”