It was a short and pleasant interview - the officer asked me questions about how my fiancee and I met, a few personal details about her and her family and why we aren't getting married in India. It was over in less than 5 minutes. However, the waiting time between collecting your documents and the interview was almost 90 minutes. I'm not sure if K-visa applicants get called towards the end but I did notice those with tokens much later than mine getting called earlier than me. The visa officer was courteous and apologized for the wait. Overall, a very straightforward, professional and painless experience.