Great point. Or as Daniel Geer et al put it[1] (discussing security, but applicable in general): "The central enemy of reliability is complexity. Complex systems tend to not be entirely understood by anyone. If no one can understand more than a fraction of a complex system, then, no one can predict all the ways that system could be compromised by an attacker. Prevention of insecure operating modes in complex systems is difficult to do well and impossible to do cheaply: The defender has to counter all possible attacks; the attacker only has to find one unblocked means of attack. As complexity grows, it becomes ever more natural to simply assert that a system or a product is secure as it becomes less and less possible to actually provide security in the face of complexity."