9. When Cuban Vs. Nellie Really Started (2003)

One of the only things Cuban and ex-Mavs coach/GM Don Nelson can agree on is that their relationship took a permanent turn for the worse during the 2003 Western Conference finals. They disagreed on whether Dirk Nowitzki should play with a knee injury. Cuban, armed with team doctors' assurances, argued Nowitzki should play, but Nelson refused to use the forward. (Glenn James/NBAE via Getty Images)