I'll agree that complexity is part of the Ball of Mud phenomenon. The worst I've seen was attributable to what used to be called 'coupling', mostly accidental

I'll agree that complexity is part of the Ball of Mud phenomenon. The worst I've seen was attributable to what used to be called 'coupling', mostly accidental, incidental, or pathological, between different parts of what was said to be a 'system,' mostly for lack of a better word. With all the incomprehensible consequences of any software changes, bug fixes of the buggy code were discouraged by management, because the average number of new bugs caused by each repair was approximately equal to 1 + the number of programmers involved in creating the fix.