When you leave the military, that mission that you've been on is gone. And for some of us, if the only thing you ever really want to do was serve and execute that mission, it can be a rough transition. Jocko Willink: How many of our brothers and arms got out and that whole consumed them? You know, they didn't find purpose. Without purpose, you know, guys start drinking to depress it. It's poison," he says.