As a footnote, and back to the OP from 6 years ago (!), I have one thing to add.
I think what military service DOES instill is a certain personal discipline and mental toughness. There's an old saying that goes, "You have to learn how to take orders, before you should give them."
Beyond that, especially those who have served overseas, have a keen appreciation for what we have in this country. Most people think it's a cliché to say, "It could always be worse." G.I.s know it's true!