The author recounts a personal experience from their consulting days where a lack of clear rules led to mistakes in logging hours, resulting in financial loss for the company. They reflect on how they repeated this mistake as a leader, failing to communicate expectations during onboarding. The key issue was informal team processes that left new hires confused about mandatory steps, causing avoidable errors. The author emphasizes the need for solid documentation and a proactive onboarding strategy. They suggest that unwritten rules can lead to significant consequences for team dynamics and performance. To combat this, they recommend creating clear, concise documentation that outlines rules and workflows, ensuring everyone understands their roles. Introducing a buddy system for new employees can also facilitate knowledge transfer and make it easier for newcomers to ask questions without feeling awkward. When mistakes happen, the author advises leaders to reconsider their own communication before blaming the team member. Acknowledging that the responsibility often lies with the leader can foster a more supportive environment. They provide actionable steps to minimize implicit rules, such as documenting practices, explaining critical costs upfront, and simplifying rules to avoid confusion. This approach not only helps new hires but strengthens the entire team's performance.