What all was happening when the Rock left the WWE in 2004? I know that was when he went all in on his acting career, but it sounds like there was also some bad blood, i.e. putting over Hurricane in 2003, only for HHH to squash him to look better.
There was a bit of it, but the main issue was that Johnny Ace was supposed to be send Rock a contract renewal and never did. So Rock's contract expired after WM20 and no one noticed, at which point Vince McMahon was no longer tied to him as "Executive Producer" on all his movies. It actually cost them a fair bit of money. Rock apparently felt pretty slighted by the oversight and there was some bad blood over that for a while afterwards.