According to theINVEST mnemonic, a good user story should beValuable. This means that the user story must deliver value to the customer or stakeholder. Each user story should have a clear purpose, ensuring that the effort invested in its development contributes to the overall product value. Other criteria of the INVEST mnemonic include Independent, Negotiable, Estimable, Small, and Testable, but "Valuable" is key to justifying the user story's inclusion in the product backlog.