Researchers have found that whenever most systems—such as airports, freeways, and other such things—exceed about 90 percent capacity, efficiency drops massively. Not just slightly, but massively. This is called the “ringing effect.” The reason is that as a system nears its capacity, the effect of relatively small disturbances is magnified exponentially.
— Matt Perman
HT: What’s Best Next: How the Gospel Transforms the Way You Get Things Done by Matt Perman