OK, so you made it as simple as possible but it does not appear to be simple. Not to yourself, not to the others. How can we recognize "as simple as possible but not simpler" stage? Or even strive for complexity?

The complexity of software is an essential property, not an accidental one. Hence descriptions of a software entity that abstract away its complexity often abstract away its essence.

F.P. Brooks, Jr.: No Silver Bullet - Essence and Accident in Software Engineering; in The Mythical Man-Month, Addison-Wesley, Reading MA, 1995.

The sore truth is that complexity sells better. (It is not only the computer industry that has discovered that.) And it is even more diabolical in that we even use the complexity of our own constructs to impress ourselves.

Edsger W. Dijkstra: The threats to computer science, EWD 898.

Making simple matters complex or complex matters simple are both bad gardening techniques (Michael P. Garofalo, Pulling Onions, http:/www.gardendigest.com)