What's the most important job question you can ask?
What's the salary? What are the benefits? What's my role? What are the responsibilities? What's the workplace culture like? What are my opportunities for advancement?
Over and over again, people who write career advice will give you the same advice on what interview questions to ask. The same boring advice. The same wrong advice.
Here's the most important job interview question you aren't asking.
"Are you happy?"
People will tell you that's stupid, that's crazy, that's naive. That work isn't about happiness, that any potential hirer will think you're a fruitcake for asking such a drippy question, that whatever the answer is won't tell you anything.
Instead, it will tell you everything.
What do your salary, benefits, and responsibilities matter if you are hired for a job that makes you miserable?
Sure, how the person you ask this question answers won't tell you everything. It could be a great place to work, but your potential future boss is a miserable person. Or maybe they don't understand the question, not really, so they give you a response that doesn't tell you a lot. Or maybe they're having a bad day — like, it's Valentine's Day, but they're alone, and they're going to go home and watch "Sex and the City" reruns while eating pretzels.
It really doesn't matter what the answer you get is. It matters what you believe the answer to be.
For example, when interviewers asked me if I had any questions when I was going on interviews last year after I got downsized, I would ask a few of the questions you're supposed to ask. What are my responsibilities? What are the benefits? Is travel involved? Those questions were just me wasting time to get to the only question I wanted to ask during the whole interview.
Are you happy?
Mostly, I half-listened to what their answer was and paid more attention to what their face told me. If their immediate facial response was blank, gazing off into the distance, their mouth turning down slightly, I knew the answer. They were unhappy. Most of the time, they will tell you they're happy. They're not going to say, "No, I am very unhappy at this job. Would you like to come and work here?"
But really, because they are at work, they will think you are asking them if they are happy at work, and if they are unhappy at work, if they frown with concentration trying to figure out their response, if they stammer as they start to answer, if they tell you how happy they are while never cracking a smile, it's quite possible you don't want to work there.
Unless you want to be unhappy, of course.