Responsibility
When something isn’t quite right in your research do you explain things with excuses or reasons?
Did you do something wrong? Did you forget something? Were you careless? Were you to blame?
Words matter. Be careful how you take responsibility for something. Consider why and how something happened, what you did at the time and what you could have done.
Remember that you can take responsibility but that doesn’t mean that you’re to blame.
And remember that if there is a problem in your research you can take steps before the viva to be ready to talk about it. Writing a summary, talking with your supervisor and thinking carefully can help you talk if the topic comes up.