The real reason why Eminem and Mariah Carey had beef: Eminem and Mariah Carey had one of the most epic celebrity feuds that resulted in shady lyrics, diss tracks, and denial. It all started over 20 years ago in 2002, and while it was always thought to be because of a failed romance, producer Damion “Damizza” Young says it's actually because he wanted her to play his mom in 8 Mile.