There is a very cool quote from history that I like.
I is pretty much a reply to people who think that the knights were thoughtless lunks who could charge into battle and nothing else. It is my justification for the way charge and retreat works in the Book of Battle.

For purposes of training, games were often arranged in the following manner. Fighting-men would be deployed in a place where they could be observed. The entire group of Saxons, Gascons, Austrasians, and Bretons were divided into two units of equal size. They charged forward from both sides and came toward each other at full speed. Then [before contact was made] one side turned its back and under the protection of their shields pretended to be trying to escape. Then those who had been engaged in a feigned retreat counter-attacked and the pursuers simulated flight. Then both kings [Louis the German and Charles the Bald] and all of the young men, raising a great yell, charged forward on their horses brandishing their spear shafts. Now one group feigned retreat and then the other. It was a spectacle worthy of being seen as much because of its nobility as because of its discipline.

I pulled it from here, which is a worthy read itself.
http://web.archive.org/web/20110605021909/http://www.deremilitari.org/resources/articles/bachrach3.htm