WWE weren't just pushing John Cena as a wrestler in that 2005 / 2006 period, it was also the start of a huge effort to make him a crossover mainstream star. Vince McMahon's desperation for Cena to be the new Rock was actually what hurt Cena's popularity. Fans don't like to be told what to like, and they sure as hell don't like cheesy fakeness. And it didn't come any cheesier or more fake than Cena's "rap music" career. The song "Bad, Bad Man" was the biggest WTF moment of his music career. Including an A Team inspired music video, lines included "don't f*** with John Cena, I'm a bad, bad man."