When a system becomes sufficiently complex, so as to confound our efforts to predict its behavior, we begin speaking of probabilistic, rather than deterministic, outcomes. The convergence of mutually redistributed routing domains is often discussed probabilistically, forcing engineers to rely on lab results, rules-of-thumb, and intuition for guidance during design. And while misconfiguration no doubt lies at the bottom of nearly all pathological behaviors that emerge, I would wager these more often stem from a failure of imagination than cavalier planning.
