Which question can you ask to find out the most about a person?
@Hope
So, honestly, Hope, I like the Questions you ask Us! I think if we bother to reach into our Brains and Try to Answer them, then you Quite Possibly would know Quite a Bit about us!
Frankly, if you're asking Me, I try not to Pepper People with too many Questions. It can seem like Interrogation, or a Questionnaire, like a Research Study. I usually would try instead to take my cues from what they seem interested in, what they are wearing or saying, or what they seem drawn towards, and then try to develop that interest by drawing them out a little bit.
I have a funny little story about Questioning. I was always feeling "Questioned" as it were, growing up, and my Parents' home didn't help Matters. They had these Blazing Bright Lights in the Kitchen. When I was in the Kitchen, I always felt like I was under some Interrogation Lights.
Anyway, I guess that's not a Funny Story after all. It's just one person's response to Questions lol. I would have to say it's one of the reasons I like the Rule: "No Questions" in the Sharing Circles, because it allows the People to Develop Their Own Thinking, rather than being Questioned. Also, some people can react to questions like their very existence or worth is being questioned.
Not the response you expected probably, but then, I'm full of Surprises!

@VioletVeritas
Ask them about their religion. Its not so much what they answer but how much. If they drown on or get excited about it I know all I want to know about them.