In most cases the viva is a tough, fair, interesting conversation. In most cases the candidate finds out they have to complete some corrections afterwards. In most cases the candidate discovers that their worries about what might happen didn’t match up with what did happen.
Your viva could be an anticlimax. It might not live up to all of your expectations. It could be boring. It could be fine but not the amazing event you thought it might be.
After thousands of hours of work spread out over several years of a research programme, in the space of a few hours you’re pretty much done.
Before you can believe it, it’s all over.