You can’t prioritize without saying no.
For the sake of this discussion let’s define pod performance as the ability to consistently (or relatively frequently) meet sprint goals, which should be aimed at the most important thing.
I think one of the biggest predictors of a team’s performance is their ability to say no to new work during a sprint. It’s especially important to say no to the product owners requests for new work during a sprint, or re-negotiate the sprint commitment. Product owners will always ask you to do more work than you can do. If you think about it from their perspective, they only see the stories, and not the hundreds of tiny tasks it takes to design, plan, code, test, and automated test every code change. Don’t look at it from their perspective.
Saying yes is a commitment. “OK” is saying yes. If you say yes to things that come into your sprint after you’ve started it, you’re committing to more work. You are going to feel stressed out. Your batch size will increase, life will feel crazy.
Start a sprint with only the stories you believe you can finish, and don’t work on anything else unless you re-negotiate the terms of the sprint.
Some people believe that you should never change the stories in a sprint once the sprint is started. There are good reasons for that. Personally I think you should never increase the amount of work in a sprint (unless you’ve finished all the sprint work of course). If something else becomes “the most important thing”, you need to focus on that thing. It doesn’t mean you can do more work! Take something out, put the new thing in.
Not increasing the amount of work in a sprint is the key. You can’t increase the amount of work you can do by saying yes. You still have the same capacity, but now you’ve overloaded it, so prepare to feel overloaded.
It’s hard to say no. It’s also hard to feel stressed out all the time because you have more work than you can finish. So you get to choose, you can feel the discomfort of saying “no” to extra work, or you can feel the discomfort of having too much to do.