Tesler's Law of Conservation of Complexity states that all systems have an inherent complexity that cannot be removed or hidden. Good designs make it so that the complexity burden is on the shoulders of the product rather than the user. The complexity burden should be shifted towards the least important use cases. However, interfaces should not be simplified to the point of abstraction. When the system has taken care of as much of the inherent complexity as possible, the rest of it should be shifted away from the primary use cases to the secondary and tertiary use cases.