Asking the right questions

When creating a documentary, the cinematography is important... but there is something else that cannot get overlooked. The questions. You have one chance. This is never going to happen again. What do you ask your subject? This is what I've been contemplating recently in preproduction for the documentary (which begins this week) in Colombia. I'll be spending my time with some very interesting people who run a very small coffee farm. They all have a story to tell and I need to get it out of them. 

What would you ask?