Like it or not, we remain the possessors of potentially strong muscle, bone, sinew, and nerve, and these hard-won commodities demand our attention. They were too long in the making to just be ignored, and we do so at our peril. They are the very components of our existence, the quality of which now depends on our conscious, directed effort at giving them the stimulus they need to stay in the condition that is normal to them. Exercise is that stimulus. Over and above any considerations of performance for sports, exercise is the stimulus that returns our bodies to the conditions for which they were designed. Humans are not physically normal in the absence of hard physical effort. Exercise is not a thing we do to fix a problem — it is a thing we must do anyway, a thing without which there will always be problems. Exercise is the thing we must do to replicate the conditions under which our physiology was adapted, the conditions under which we are physically normal. In other words, exercise is substitute cave-man activity — the thing we need to make our bodies, and in fact our minds, normal in the 21st century. And merely normal, for most worthwhile humans, is not good enough… ~Rippetoe and Kilgore
You got to love Rippetoe and his to-the-point wording. Rip is a colorful character, with a unique expression of language, to say the least. Agree with him or not, he has a point and this quote really sinks in. We were made to be active beings with our time on this Earth. CrossFit provides the necessary full body stimulus which our bodies demand.