Every system has a limiting factor that determines its overall performance—the bottleneck that constrains everything else. When one feedback loop dominates with 99% influence, it shapes the entire system's behavior regardless of what else is happening. The most important part of any system is what's limiting it most, and anticipating the next constraint becomes vital once you've addressed the current one.

Nothing can grow infinitely in a finite environment—all exponential systems require both a reinforcing loop driving growth and a balancing loop constraining it. The interaction between these loops determines system limits, with finite resources like energy, space, or attention creating higher-order constraints that shape what's possible. Perfect optimization often backfires because systems need slack to survive unpredictable shocks.

Constraints breed innovation rather than limiting it—scarcity and boundaries force creative problem-solving that abundance never demands. Cellular networks exemplify this principle by inverting the problem: instead of increasing power to overcome signal limitations, engineers lowered frequency to extract more utility from limited spectrum. The frugal advantage compounds over time as small expenses accumulate into massive inefficiencies.