Just before leaving the Marine Corps in 2011, I wrote a brief reflection on what I’d learned. I wrote it from a dark bar while sipping a dark whiskey, probably listening to some dark music, but I can’t be sure of that last part. This gloomy setting was appropriate that day because it was, frankly, a dark time. I’d spent the previous 11 years in uniform doing work I truly loved. Would I ever be able to find that sort of...