Why does Wanderlei hate Rampage so much?

Did you see them during the weigh in today? Wanderlei shoved Rampage during the stare down and had to be pulled off by Dana. By most accounts, these are two of the nicest, humblest guys in the UFC. Yet Wanderlei claims to hate Rampage with a pion. What did Rampage say or do to Wanderlei to deserve this hostility? If anything, Rampage should be upset after getting his a$$ kicked twice by Wanderlei in Pride. I just don't get how two such nice guys could hate eachother like this. I mean we're not talking Tito and Shamrock or Hughes and Serra here!