I interviewed my friend who serves a military service as a KATUSA. I made some questions before I interviewed him. Through the result, I learned that every soldier have their own problems.
The longest answer I got was the question "What is the most difficult thing when you work with U.S. soldier?" Because he has to pick "the most difficult thing" among the many difficulties, he gave me the longest answer.
The shortest answer I got during the interview was driven from the question "Who you like the most among the G.I.s (General infantry, normally means U.S. soldier)?" Because he could easily answer the name of soldier, it was the shortest.
Many people in Korea think that military service as a KATUSA is really easy. But when I asked a question, "What is the most difficult thing in your military life?" the answer was pretty interesting, because it was distant so far from the conventional thoughts.
Because the relationship with the interviewee was quite friendly, it was really easy to ask questions. But if I have to interview someone who I do not know well, I will prepare more questions in order to get a better result. Also, I will reword his words to make him comfortable.
By interviewing my friend, I found that check my phone during the interview could make the interviewee uncomfortable. So, I recommend you to avoid this.