Either, Garnett would whip him into shape, or he'd be out of Boston within 2 seasons. I'd take the risk, but meh.
It's pointless to have a star player if he chooses to not stay on the court at times.
Cousins would have to be a leader-type in order to be the star of a team, but that doesn't look like it's happening anytime soon.
At least Rasheed just spoke his mind, he didn't get all those t's just for the sake of being a punk (mostly).