In user interviews, I often say "very interesting" or "that's an interesting point" or "very helpful" in response to users answer. "Interesting" is a perfect word choice because it has a neutral feeling, doesn't really mean good or bad. Sometimes it would be very repetitive for keep saying those in a long conversation. Would you suggest any other phrases or words to response to users?
What are filler words that you can use for responding to users' saying in user interview?
I sometimes use...
"Curious, what else?" or "I'll note that, continue?" or "Do you see other items of interest?" or "Great observation!"
Each of these is situational, and I use them to both acknowledge the comment and prompt to move forward.