With his easygoing, guy-next-door charm, Luke Bryan is one of the defining figures of bro-country, the strand of party-hearty music that dominated mainstream country in the 2010s. Bryan embodies the sweeter, friendlier side of bro-country. He sings about trucks, country girls, beer, and the outdoors -- the prevalent themes of his subgenre -- and he does it to a big, bright beat that borrows from pop and rock but conveys 21st century country: music made for suburbs and sports bars, not backwoods honk tonks. All these elements were in place on Bryan's earliest hits "All My Frien...