I agree that addressing the student and asking how they feel about their paper is important. I think this shows you recognize their efforts and you respect them. Additionally, individual conferences are a nice way to interact with students that might otherwise be shy in front of their peers. I like to take a little time to ask them some questions to help build rapport. As one of my colleagues calls it "shooting the breeze". In doing this, i hope students feel more comfortable during class, and have a lowered affective filter that will allow them to fully participate. Lastly, individual conferences are a great time to check-in with students that might be struggling with the class. I always try to prepare some ideas/solutions for students that I notice are struggling and encourage them to contact me, when they are in need of help or not understanding class content. When you deliver this information one-on-one, I have found the students take your advice to heart. When, I make suggestions or encourage students to reach out to me if they are struggling as a message to the whole class, I never get any follow-ups.