Depends. The best interviews tend to be conversational. Being able to steer a conversation to things you want to highlight is a strong interviewing skill. Interviewers often indicate that they consider an interview bad when the interviewee only answers questions asked, has not much to say, doesn't seem that excited to be there, and that getting information was like pulling teeth. This is your chance to sell yourself over everyone else in the application pool. Don't be too passive or lukewarm. This is not a formality, to weed out crazies -- people get in on the strength of their interviews, and can get waitlisted on the weakness of them too..