For many years Admiral Hyman Rickover was the head of the United State Nuclear Navy. His admirers and his critics held strongly opposing views about the stern and demanding Admiral. For many years every officer aboard a nuclear submarine was personally interviewed and approved by Rickover. Those who went through those interviews usually came out shaking with fear, anger or total intimidation. Among them was Ex-President Jimmy Carter who, years ago, applied for service under Rickover.
This is his account of a Rickover interview:

I had applied for the Nuclear Submarine Program, and Admiral Rickover was interviewing me for the job. It was the first time I met Admiral Rickover, and we sat in a large room by ourselves for more than two hours, and he let me choose any subjects I wished to discuss. Very carefully, I chose those about which I knew most at the time, current events, seamanship, music, literature, naval tactics, electronics, gunnery, and he began to ask me a series of questions of increasing difficulty. In each instance, he soon proved that I knew relatively little about the subject I had chosen. He always looked right into my eyes, and he never smiled. I was saturated with cold sweat.
Finally, he asked a question and I thought I could redeem myself. He said, “How did you stand in your class at the Naval Academy?” Since I had completed my Sophomore year at Georgia Tech before entering Annapolis as a Pleb, I had done very well and I swelled my chest with pride and answered “Sir, I stood fifty-ninth in a class of 820!” I sat back to wait for the congratulations which never came. Instead the question came. “Did you do your best?” I started to say, “Yes, sir”, but I remembered who this was and recalled several of the many times at the Academy when I could have learned more about our allies, our enemies, weapons, strategy, and so forth. I was just human. I finally gulped and said, “No, sir, I didn’t always do my best.”
He looked at me for a long time, and then turned his chair around to end the interview. He asked one final question, which I have never been able to forget or to answer. He said, “Why not?” I sat there for a while shaken, and then slowly left the room.

Graham Twelvetree in Get The Point Across p34-35