Millitary Grammar

i was watching a TV show that had a boot camp scene in it, and noticed the soldiers going "SIR YES SIR" This is peculiar construction that in any other circumstances seems ridiculous. You don't see people going around saying "Bob, yes bob." It is a unique form of speech used in the military, and is instantly identifiable. It almost feels as if this construction is there to help differentiate military life from civilian life.