"Thank you," and "I'm curious" - Helpful phrases as an interviewer

I wrote a quick post on two phrases that have helped me as an interviewer during interviews that weren't going well: "Thank you," and "I'm curious."
This is actually good for any field too!
I love this! It really just all boils down to showing respect and a genuine interest in what the other person is doing - so any words of acknowledgement will make someone feel at ease.