Metrics-based product development enables companies to quantitatively define and measure success, guiding efforts toward prioritized goals, often through a singular "North Star metric." However, focusing solely on success metrics can lead to unintended negative consequences, such as decreased overall engagement or alienating potential user bases. To mitigate these risks, counter metrics, or "guardrail metrics," are employed to monitor and prevent adverse effects while optimizing for success. For instance, in the context of a fitness app, while increasing "time spent exercising" is a goal, counter metrics like "time spent on informational content" and the Net Promoter Score can help ensure balanced user engagement and broader appeal. Balancing success and counter metrics is essential to maintaining a product's overall health, aligning data-driven and product-focused thinking, and ensuring sustainable development and growth.