What is the most important question to ask an interviewer?

Today I went to a group interview and the interviewer said that nobody had asked the most important question yet. There was a lot of good questions that were asked, but nobody could think of what was the most important question. His or her name. maybe: what can this job lead to in the future for me?

I don't know if this is the "most important" question to ask, but it is a question I used a few times and have had very interesting responses. When I am asked if I have any questions, I turn the table on the interviewer and ask them why THEY chose to work for the company and how they got started. Believe me, this question works great. It shows you are interested in the company and the interviewer. It also gives the interviewer a chance to talk about themselves, and let's face it....we all like to talk about ourselves to a receptive audience! I've found out many interesting things about the company and it's employees from asking this question.

1.What happened to the holder of the position/
2.If the interviewer has any concerns that will prevent him,her from selecting or recommending you for the position?

Why do you want this job?