Great question! And also a tough one. Here are a few ideas:

- I might think of a few prompts (in advance) for the people who don't find it easy to tell "stories." If I was asking about grocery shopping I might start by asking the person to think of the last time they shopped for groceries and then ask a few follow-ups like: Around what time was this? What were you up to before going to the grocery store? Were you alone or with someone? If you can keep a welcoming tone, this shouldn't feel like too much of an interrogation, although that's a risk.

- Be curious about anything the person _does_ say. So if they mention that cabbage was on sale, so they decided to buy it to make coleslaw, ask about this: How did you find out cabbage was one sale? Do you typically plan meals around discounted foods?

- Ask about the last 3 trips to the grocery store and ask a few follow-up questions for each. This way you get a broader picture.

- Could you say something like this to the person: "It would be help me a lot if you could share some of the details related to your grocery store trip. This may sound weird, but you can, for example, think that you'd be telling me a story. (I'll leave it up to you to decide whether saying something like this is too weird.)

I hope this helps!

I think the key is to prepare a little "too many" questions so you don't feel clueless when someone is a little less talkative. And then to listen as attentively as you can.