7. Jon Snow
Of all the characters on the show, Kit Harrington as Jon Snow stands out as the one whose looks least match those of his character. In some ways this is not so much a reflection of his performance as his physique. Jon Snow is described as lithe, slight and agile whereas Robb Stark is strong and broad, yet in the show Kit Harrington's build is very similar to that of Robb as played by Richard Madden. Kit's performance of Jon makes him an extremely sulky, morose bastard (sorry) and while in the books Jon certainly can be a whiny SOB, it's always been my impression that he is more melancholy than outright miserable. In the show Jon is aggressive, actually embodying much of the anger I'd have hoped to see in Stannis. It also doesn't help that Kit Harrington looks far too old for the part, even given the fact that the writers intentionally "aged up" all of the child actors. And now I realise I'm just nitpicking, but while I'm at it, I hate the fact that they gave Jon Snow curly hair and a pissy five o'clock shadow of a beard. Lord Snow should have a shock of straight black hair and no fuzz on his chin whatsoever (IMHO)!