Ali may of seen it initially as "Ballyhoo" but his incessant Baiting of Frazier certainly lit a fuse of Hate in Frazier...Ali turned on and off the ..Dislike when it suited him, Manila saw the last opportunity of both to Physically vent their feelings, and as we know...vent them they certainly did. I understand Jerry Quarry had Little time for Ken Norton, who supposedly made inappropriate comments to Jerry's wife calculated to Wind Jerry up...They also had a verbal altercation in a car park after the fight according to the recent "Hard Luck" book on Jerry.
Froch - Dirrell, is not the best of friends either, but I don't know how the were before their fight.
I hear that Barrera and Morales aren't too fond of each other. Cotto and Margarito (the second time.) Frazier vs. Ali (all three times, probably most in the first and third encounters) Floyd vs Zab probably counts. SRR vs Basilio Golota vs. Bowe II
Hopkins Roy jones too I love the second fight how they just feint the crap out of eachother and smile after it