I'm Navy.
One of my friends (he's Army) had his girlfriend dump him this year because he's in the military. Thing is, he had almost two more years left here at the Royal Military College (think West Point) and except for a few months of summer training, he was going to be here all the time. Just imagine if he'd been deployable.
I think it helps the game, if only because of confidence; it seems especially true for those who have done tours: being somewhere where people want to kill you and where you could die at any moment puts things back in the proper perspective, I'd assume. Between confidence and the sense of humour everyone seems to develop (to cope with all the bullcrap), the game gets a lot better.