But my question is this. Since I'm still new to Miami, did they used to dislike each other? I've only picked up bits and pieces, but that's what I thought I'd read.
Oh, yeah. They had major problems. In one episode last season (I can't remember which one), Ryan claimed credit for work Eric did, and he never really apologized. Their relationship degraded after that, and the two men ripped on each other constantly after that. They both bear some responsibility for their problems.
Relations tended to get really bad in episodes like "Killer Date," where Eric overreacted when Ryan investigated one of Speed's old cases.
Of course, all of this was due to the simmering sexual tension between them. At least partially.