This "sir, yes sir" business, which would probably sound like horseshit to any civilian in his right mind, makes sense to Shaftoe and to the officers in a deep and important way. Like a lot of others, Shaftoe had trouble with military etiquette at first. He soaked up quite a bit of it growing up in a military family, but living the life was a different matter. Having now experienced all the phases of military existence except for the terminal ones (violent death, court-martial, retirement), he has come to understand the culture for what it is: a system of etiquette within which it becomes possible for groups of men to live together for years, travel to the ends of the earth, and do all kinds of incredibly weird shit without killing each other or completely losing their minds in the process. The extreme formality with which he addresses these officers carries an important subtext: your problem, sir, is deciding what you want me to do, and my problem, sir, is doing it. My gung-ho posture says that once you give the order I'm not going to bother you with any of the details--and your half of the bargain is you had better stay on your side of the line, sir, and not bother me with any of the chickenshit politics that you have to deal with for a living. The implied responsibility placed upon the officer's shoulders by the subordinate's unhesitating willingness to follow orders is a withering burden to any officer with half a brain, and Shaftoe has more than once seen seasoned noncoms reduce green lieutenants to quivering blobs simply by standing before them and agreeing, cheerfully, to carry out their orders.
Neal Stephenson, Cryptonomicon
military