That's the big mistake a lot of people make when they wonder how soldiers can put their lives on the line day after day or how they can fight for something they may not believe in. Not everyone does. I've worked with soldiers on all sides of the political spectrum; I've met some who hated the army and others who wanted to make it a career. I've met geniuses and idiots, but when all is said and done,we do what we do for one another. For friendship. Not for country, not for patriotism, not because we're programmed killing machines, but because of the guy next to you. You fight for your friend, to keep him alive, and he fights for you, and everything about the army is built on this simple premise. 
Nicholas Sparks, Dear John
insightful