Absolute Base Class

Base classes should be as abstract as possible (they can be defined as abstract classes). Depending on use case, they should contain no more information than what is absolutely necessary - even if it is only the name of the object! Inside of a class-hierarchy all affected classes (objects) can be handeled similar. Thats exacting than if you handle all similar classes of a class-hierarchy as absolute base class "object". Once particular classes get specify tasks/Properties, interfaces can be used.