One of the twelve principles behind the Agile Manifesto says: “At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly”. Agile is all about adjustments here and there, learning, fine-tuning and responding to change.
It’s really hard to adjust and fine-tune effectively if we don’t pause to find out where adjustments are needed. The Sprint Retrospective is the mechanism that Scrum teams usually use to fulfill this principle of inspection and adaptation. Unfortunately, the retrospective is often treated like an add-on or a luxury and performed only “if there’s time”.