All policies make sense based on their underlying assumptions; otherwise no one would be tempted to formulate them or carry them out. Yet, they often have unforeseen consequences that lead to very different outcomes than the ones imagined. Worse, unlike the characters in folk tales who end up realizing their mistake, the unforeseen consequences of policies are typically diffuse and indirect, therefore difficult to trace to their causes. In this fashion, we become lost in a maze of unforeseen consequences.

from this blog post.

The value of System Dynamics is exactly to surface the underlying assumptions, thus minimizes the unforeseen consequences.