Agile is an attitude, not a technique with boundaries. An attitude has no boundaries, so we wouldn’t ask ‘can I use agile here’, but rather ‘how would I act in the agile way here?’ or ‘how agile can we be, here?
The real test is not whether you avoid this failure, because you won’t. It’s whether you let it harden or shame you into inaction, or whether you learn from it; whether you choose to persevere.
Retrospectives should match the rhythm of the work they’re evaluating. The questions to ask yourself are ‘How fast are we learning? How fast do we want to learn?’
People don’t change because you want them to change, people change when they’re ready to change. So, understanding why, and when, and how people change is probably the biggest thing you can learn.