Fundamental Goal of OOP

A fundamental goal of OO design is to place the behaviour (methods) as close to the data they operate on (attributes), so that changes are less likely to propagate across multiple classes.

http://www.codemanship.co.uk/parlezuml/metrics/OO%20Design%20Principles%20&%20Metrics.pdf

Big Ball of Mud and Intolerance of it

The following may be one of the most quoted paragraphs in software literature (my emphasis added):

A BIG BALL OF MUD is haphazardly structured, sprawling, sloppy, duct-tape and bailing wire, spaghetti code jungle. We’ve all seen them. These systems show unmistakable signs of unregulated growth, and repeated, expedient repair. Information is shared promiscuously among distant elements of the system, often to the point where nearly all the important information becomes global or duplicated. The overall structure of the system may never have been well defined. If it was, it may have eroded beyond recognition. Programmers with a shred of architectural sensibility shun these quagmires. Only those who are unconcerned about architecture, and, perhaps, are comfortable with the inertia of the day-to-day chore of patching the holes in these failing dikes, are content to work on such systems.

http://www.laputan.org/mud/mud.html