A lion is capable of catching mice for food, but if it spends all of the time doing so it won’t survive.
A gazelle could be harder to hunt for but will, if caught, provide everything the lion needs.
That’s a little paraphrasing of a famous business metaphor about focus, but the broader point is on the focus that we give to things. Focussing on the small, little, easy things to do might make you busy, might give you lots to do, but it might not reward your effort or move you closer to your goals. The harder tasks are more challenging, but if you succeed with them then they’ll give you what you need.
You could spend your time in preparation for the viva catching mice. Checking your thesis again and again for typos. You could obsess over sections trying to memorise things. You could look over lists of questions and try to think about what you would say.
But these mice won’t satisfy your sense of readiness for the viva.
You need to focus on the bigger, more challenging tasks: reflecting on your progress, building your confidence, rehearsing for being in the viva, reading your thesis carefully once. These gazelle-tasks take effort, they’re thoughtful, but they’ll reward your preparation.
We tend to get more of what we focus on. What will you focus on as you prepare for your viva?