Why does Jim hate Denny Falcone so much?

Well...it's been mentioned in passing by Opie but the proof is every Thursday lately that Jim simply won't be on the air at the same time as Dennis Falcone. While I know that Falcone isn't exactly FUNNY per se, he is a pleasant guy with a very unique, though out-of-date talent (that of the stereotypical 50s-60s-70s DJ). Considering the springboard to comedy that Dennis can often be, why does Jim refuse to let the guy on the air when he is there? I, for one, find Dennis Falcone ten times more entertaining than Sherrod Small yet Jimmy has no problem being on with that talentless motherfucker.