Pay attention to what is important, not just what is quantifiable. - Donella Meadows

Before you disturb the system in any way, watch how it behaves. If it's a piece of music or a whitewater rapid or a fluctuation in a commodity price, study its beat. If it's a social system, watch it work. Learn its history.

In physical, exponentially growing systems, there must be at least one reinforcing loop driving growth and at least one balancing feedback loop constraining growth, because no system can grow forever in a finite environment.

The bounded rationality of each actor in a system may not lead to decisions that further the welfare of the system as a whole.