Barry Bonds and Jeff Kent
Neither of these guys would exactly be labeled "team first," and with what's come out about Bonds since his retirement, should we wonder that he had a little pent up aggression? The two had been trading barbs for some time when everything came to a head in 2002's "Slugout in the Dugout," which was really just a lot of cursing and shoving. After the public incident, Kent admitted that it happened all the time. What did they fight about? Who knows? Maybe who rocked a more awesome 'stache?