What is a sprint retrospective?
A sprint retrospective is the meeting an agile team holds at the end of every sprint to inspect how they worked together and decide what to change. The goal isn't to relitigate every story or celebrate the demo - it's to find one or two specific improvements the team will commit to for the next sprint.
A good retrospective follows a predictable arc: set the stage, gather data, generate insights, decide on actions, and close. The format you pick (Start/Stop/Continue, Mad/Sad/Glad, 4Ls, Sailboat, Plus/Delta, and so on) is just a frame for the "gather data" phase - they all work as long as the team commits to concrete, owned action items at the end.
Retrospectives are the single most important meeting in scrum. When teams stop running them - or run them on autopilot - they quietly stop improving. A 30-to-60 minute retro every sprint, with a fresh format every few months, is one of the highest-leverage habits an engineering team can build.