The warm air that night in Valle Grande bid us outside once again, so we donned our sweaters and walked to the middle path of the tiny cliffside village in Argentina. The ten teenagers in my group huddled around me and my guitar, and I fiddled around, playing this or that, nothing special. We laughed together over nineties throwbacks and acoustic renditions of rap hits. It was comfortable -- something I had done countless times before. You see, back then...