Hey John, how was your viva? “It was fine.”
Hi Kate, how was your viva? “Fine, thanks.”
Tom, how did you feel about your viva? “Fine.”
I asked lots of friends about their vivas while I was a PhD student. They all said it was fine and I left it at that. When my own came around I felt fine too, until the night before. Insomnia hit and I lay awake for hours and hours. I didn’t know what to expect and now I wasn’t fine.
Fine is nice, fine is reassuring, but fine doesn’t tell you anything. Ask specific questions, push for specific answers and set some reasonable expectations for the viva.
Then you will be fine.