"A beginning programmer writes her programs like an ant builds her hill, one piece at a time, without thought for the bigger structure. Her programs will be like loose sand. They may stand for a while, but growing too big they fall apart.
Realizing this problem, the programmer will start to spend a lot of time thinking about structure. Her programs will be rigidly structured, like rock sculptures. They are solid, but when they must change, violence must be done to them.
The master programmer knows when to apply structure and when to leave things in their simple form. Her programs are like clay, solid yet malleable."
-- Master Yuan-Ma, The Book of Programming
Powerful.