(09 Aug 2015, 6:43 pm)MrFozz wrote Short and sweet answer
To elaborate, RAW was considered the flagship brand the last time around. Certain wrestlers twisted on when they were drafted to Smackdown (or ECW) because it was viewed as 'second-tier' (or third-tier). Shortly before his little episode, Benoit was drafted to ECW. Reportedly, this caused him to grow even more despondent as he felt he'd been demoted despite being booked to win the ECW title from CM Punk (which, for obvious reasons, didn't happen).
Some wrestlers have fragile egos. However it is presented, one brand is going to favoured over the other. Being on the 'lesser brand' causes problems.