In a musical sense, I'd say it's the ability to pick up on a song, and play it reasonably well by ear based on lessons and practice. In a personal sense, I'd say it's experiencing the pure enjoyment of a well crafted song and relaying that to friends and family on a guitar. Overall, music is the back drop of many lives and enriches those who strive to learn more about it. Like golf, it can never be mastered, only played.