The 'map is not territory' mental model explains how abstractions compress reality and always carry hidden limitations. Using a real-world example of a failed API integration based on outdated vendor documentation, the author explores two perspectives: being a consumer of maps (asking what purpose they serve, whether they're current, and what they omit) and being a creator of maps (stating purpose clearly, knowing your audience, and adding timestamps or validity criteria). Over-planning is framed as over-trusting a map of the future, with diminishing returns past a certain point of detail.