Individuals will continually pursue trades until the mutual gains are exhausted. Market agitation reflects the changes being made by market participants in their attempt to bring their plans into consistency with the plans of others as embodied in the data of the market.
Obviously Mises, Hayek, and Rothbard all make this point explicitly in their work, and a great number of economists makes this point about market agitation implicitly in the stories they construct to help students understand the economic logic of competitive markets. But to my mind, one of the best communicators of this logic is Israel Kirzner.
In Market Theory and the Price System, Kirzner states: "If a market is not in equilibrium, we have seen, this must be the result of ignorance by market participants of relevant market information. The market process, as always, performs its functions by impressing upon those making decisions those essential items of knowledge that are sufficient to guide them to make decisions as if they possessed the complete knowledge of the underlying facts." (240, emphasis in original)
Later in his career, Kirzner would make the important distinction between the underlying variables of the market (tastes, technology and resource availability), and the induced variables of the market (prices and profit/loss accounting), and he explained how the market process can be described as the continuous activity that results from individuals on both sides of the market trying to satisfying their plans for betterment. When the production plans of some dovetail with the consumptions plans of others, the induced and underlying variables are consistent with one another. If no mutual consistency exists, then economic activity continues because it will be in the interest of the parties to continue to seek a better situation than they are currently realizing.
Relative prices guide us in decision making, profits lure us in our decisions, and losses discipline us in our decisions. This is how the price system impresses upon us the essential items of knowledge required for plan coordination.
The science of economics is born out of the puzzle that the coordination problem presents to our imaginations. The solution to the puzzle is the entrepreneurial market process. And the resulting order of the market system is the miracle that should inspire our intellectual awe and amazement and attract subsequent generations of students and scholars to want to better understand how market forces work in theory and practice. Focusing our intellectual attentions on the conditions associated with the state of rest (when plan consistency is achieved) more often than not impedes understanding by trivializing the miracle we witness daily. While the characteristics of a competitive market equilibrium are essential to our economic understanding, we must nevertheless focus attention on how that equilibrium is brought about through the continual adjustment of relative prices that accomodate changes and guide individual decision makers in their necessary adaptations to shifting market conditions. This is how markets work to ensure that individuals realize the mutual gains from trade and the mutual gains from innovation, and realize the full benefits of social cooperation under the division of labor.