From the Scrum guide:
The Scrum Master serves the Product Owner in several ways, including:
- Finding techniques for effective Product Backlog management;
- Helping the Scrum Team understand the need for clear and concise Product Backlog items;
- Understanding product planning in an empirical environment;
- Ensuring the Product Owner knows how to arrange the Product Backlog to maximize value;
- Understanding and practicing agility; and,
- Facilitating Scrum events as requested or needed.
How much are you coaching the PO and the Dev Team? Are you just a secretary or a proactive SM? Are you stressing the PO to create right user stories or just accept everything he ask?