I don't owe you a mothafuckin' thing
Eminem describes more elaborately in interviews that this is aimed at family members who believe that Em' owes them money just because they have the same blood. Em' doesn’t owe his family shit, they weren’t there until he got famous.
The preceding lines also suggest that Eminem is speaking to his listeners who he believes approach him as if he owes them something because they are fans, like photos, autographs, etc.
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