The only way to write complex software that won't fall on its face is to hold its global complexity down - to build it out of simple pieces connected by well-defined interfaces, so that most problems are local and you can have some hope of fixing or optimizing a part without breaking the whole
Eric S. RaymondAnybody who has ever owned a dog who barked when strangers came near its owner's property has experienced the essential continuity between animal territoriality and human property. Our domesticated cousins of the wolf know, instinctively, that property is no mere social convention or game, but a critically important evolved mechanism for the avoidance of violence. (This makes them smarter than a good many human political theorists.)
Eric S. Raymond