It’s nice when someone says, “Good luck!” before your viva. It helps to know that others are thinking of you and wish you the best.
At the same time it’s important to remind yourself that your success doesn’t need luck. The viva isn’t random; passing isn’t subject to simple good luck.
Through your PhD you will have been fortunate – you have worked hard and that has worked out – but you’ve not been lucky. Your success is built on foundations of time, skill, knowledge, effort and persistence.
“Good luck!” is nice and not to be discouraged – but don’t believe for a moment that your success on viva day is lucky in any way.