adding to the store clerk idea, questions like how they deal with ethical issues when it arises at the most oddest of times, and exactly how stressful it is to deal with customer complaints and stuff maybe.
another interviewing suggestion: a teacher! (madrassah teacher is great too) how they deal with all sorts of kids in a classroom, how they feel about being with children for such a long period of time, the boring part of it all, the most exciting thing about it... basically the pros and cons to it.