How true it is I don't know, but I was told today ( a usually reliable source), that Roy was still pissed at Niall Quinn over the WC 2006 troubles concerning the Rep. of Ireland team, and before he took the managers job, Keane told Quinn as much. Quinn accepted that fact but insisted that it shouldn't make any difference as far as Sunderland FC were concerned.
Roy still took the job at Sunderland but on the understanding that he would only converse with Quinn via text messages, and that they should never need to meet face to face.
Quinn was also banned from the dressing room at all times, and banned from the training ground at all times. Quinn agreed to all of this.
Also it seems that Roy had quite a few players that he didn't get on with, and he let them know that he regarded them as overpaid and over rated prima donna's, who needed to learn a few lessons the hard way, i.e. the Roy Keane way.
A few players sulked and turned against him it seems. They feigned injuries so as to miss training and matches, and they were rewarded by Roy with losing their place in the team.
The same players went whinging to Quinn, who asked Keane for an explanation, which Keane refused to give, stating to Quinn that the agreement was that only he (Keane) would make decisions regarding team matters, and that it was none of Quinns business.
Quinn insisted on an explanation. Thats when Keane told him to stick the job, and he left.
Sounds like Roy.