Most interviews end with something like, "Do you have any questions about our company?" My favorite response is something like this:
In every company, there are issues and problems that everyone seems to be concerned with. For example, at my last job, there seemed to be a division between the "old timers" and the new wave of recent hires. We were also constantly trying to figure out our focus. (Insert your own examples here.) What kinds of things do most of your employees tend to be concerned with or worry about?
I have never met an interviewer who wasn't totally surprised by this question. I've also never met an interviewer who didn't have something interesting and insightful to say at that point. Most have even relaxed and changed from interview-mode to friendly-conversation-mode.
Asking "what do your employees worry about?" is a deep question that few people, even top managers, can bullshit their way through unprepared. If your interviewer says something like "All of our employees are completely happy", smile, shake hands, and leave. You don't want to work for someone who thinks that you'll believe that answer.