2PM debuted in 2008 as “beastly” idols: irreverent, breakdancing bad boys with a tendency to flash their abs on television. Their music is equally tough and intense, from fierce, athletic dance tracks to melodramatic R&B jams. The South Korean crew are best known for anguished lyrics about bad break-ups, but they bring the same passion to their more lovelorn numbers or even a song about letting loose in the club.