A few days ago, Florida Georgia Line posted a video on Instagram of one of their concertgoers singing “H.O.L.Y.” at the top of his lungs with the caption: “You Can’t Mistake Passion. We love this. 👊🏻” After more that 338,000 views, the “Mountain Dew Guy”—as he’s affectionately been dubbed thanks to his shirt—has become a…… MORE