Systems Theory has multiple lineages: From Hegel’s System, through General Systems Theory, to Systems Dynamics, cybernetics, and various approaches to various complex systems like healthcare. This article develops a distinction between those approaches to complex systems that stem from a common trunk: the insight that all things are interconnected. Arrogant systems thinkers aspire to a totalizing grasp of the whole. Humble systems thinkers start from the same premise of interconnectedness, but recoil from totalization and become pessimistic about the possibility of avoiding unintended side effects of any intervention in complex systems.