Have you been to a Sprint Review where someone sings out, "good job"?
When this happens we might feel happy or encouraged to continue doing whatever it is we did in the review but what does this comment really mean? The idea that someone calls over their shoulder "Good Job" as they leave a meeting, can leave the team in a slight quandary, what exactly was good?
Scrum Teams need to be able to improve in areas where improvement is warranted. Having constructive criticism is healthy for the team and can help them focus on improving whether that be taking a valuable behaviour or practice and making it better or re-thinking actions and activities that don't add much value. The key is getting valuable feedback. For the Scrum Team, it's important to get as specific as possible about what someone thought was good (or in need of improvement) but more importantly, is why they thought to mention it in the first place.
Understanding why is arguably more important than the what in two aspects: 1) it can bring the Scrum Team insight to what the stakeholder values and 2) it can inspire the Scrum Team to design and build better solutions to meet stakeholder expectations of valuable software. For example, if a stakeholder says they liked the demo segment of the sprint review because it showed an easy way to make a credit card payment, the Scrum Team might conclude that the stakeholder values simplicity in the user experience. The Scrum Team might also conclude that in the future, they'll put a little more attention in the UX design to exploit simplicity.
Scrum Teams need feedback to self-improve and need to find the best way to get the gather this information. The easiest way is for the Scrum Team to listen for all stakeholder comments during any of the team's Inspect & Adapt events (daily standup, sprint planning, sprint review). The team may need to follow up with the stakeholders to understand the what and why of their statements. Through the practice of 'Active Listening' and developing a deeper understanding of stakeholders intent, the Scrum Team can improve and provide greater value to the team's customers and stakeholders.