Systemic Dependencies for Public Service
One of the things that I'm most drawn to regarding public service is its systemic nature. In the United States, government is federated by design, and taken as a whole, constitutes the largest "system" that I'm aware of. Beyond just the technical systems, the system of government is composed of policies, people, and a network of agencies that coordinate (or don't), to deliver public services citizens expect and rely upon.
Estonia is a much smaller system, compared to the United States, yet has many of the same sub-systems any government is made of. This interactive visualization of Estonian government on YouTube begins to convey some of the interdependencies of government as a system.