Summary

"It is my firm and sincere belief that the questions you ask in a job interview are actually more important than the answers you give. When you ask a question, it is an opportunity to show how well you prepare for meetings and, specifically, how well you have researched the employer and the interviewers.
The most important question you can ask is focused on the after-interview phases of the hiring process: the thank-you email. A good thank-you can rescue a fair interview; a bad thank-you can ruin a good interview.
Here's the question: If I were to get the job, what would I be able to do to make your life easier? Ask every interviewer and write down their answer. This also means that at the start of an interview you need to get the email address of all the interviewers. (If someone says, "Just write to so-and-so," then that's what you do. But let's assume that everyone provides their email.)"