I got a note from an anonymous seminar participant:
I have written the perfect thesis. Should I worry about the viva?
If the first statement was true, I could see no reason why they should. If their thesis was perfect, really, why would they need to worry? If I had a perfect thesis, there wouldn’t be much point!
Small problem: there is no perfect thesis. Imperfection is inevitable. The perfect thesis is an impossibility.
But an imperfect thesis doesn’t automatically mean that someone should worry. They might anyway, because they have doubts, or questions, or 101 concerns. And there could be a problem in any imperfect thesis that leads to tough questions or tricky corrections: both are part of the process, neither “should” be worried about.
An imperfect thesis doesn’t mean you failed. It means that you didn’t achieve the impossible.
You have a thesis. You have you. You have everything you need to beat back your worries and succeed in the viva.