A quantity growing exponentially toward a limit reaches that limit in a surprisingly short time. - 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.

A delay in a balancing feedback loop makes the system likely to oscillate.

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