I've been working in "Agile" for a while and am working to move more towards agile at a new company. One of the problems I have always sort of encountered is effective integration of QA within the sprint.
We've done better at getting stories to QA earlier and shortening that feedback loop, but in the example of a 2-week sprint it was always inevitable that the last stories would get to QA late in the sprint, so QA would finish testing within the sprint but what does the developer do? They're done and have delivered all their stories, short of anything coming back from QA/UAT. How do we ensure they aren't just twiddling their thumbs for the last day-2 days of a sprint?