OK, the "what Draco really thinks" bit is not entirely implausible. It does make me wonder just how good an actor he's supposed to be (vis a vis his encounters with Harry Potter) though. Was that really all just a put-up because he was afraid of word getting back to Lucius if he wasn't an arsehole?
At least some of the time his spoilt-brat nature appears to be genuine (e.g. bribing the quidditch team with brooms to get him seeker position).