Six times the Harry Potter cast broke the rules of the books

The world just doesn't seem right, does it? Draco Malfoy a Gryffindor? OK, so he has some redeeming qualities. JK Rowling clearly thinks he could have been in Gryffindor had he made a few different decisions (OK, many). But in summary, nope, nope, nope, nope, nope... #DracoandSlytherinforlife

Michael Gambon, director Alfonso Cuarón and Alan Rickman - aka Professor Snape - set up a practical joke while filming Harry Potter and the Prisoner of Azkaban. Poor innocent Daniel Radcliffe was doing his best pretend-to-be-asleep-but-not-really-asleep acting only to discover a fart machine had been hidden in his sleeping bag. Tut tut. Snape wouldn't put up with such tomfoolery. Ears have been clipped by the Potions Master for far less.

Was Ron hit with a Memory Charm or something? Draco is not a pal. Ditch the celebratory t-shirt!

Now, now, Neville, if you haven't got anything nice to say... which you should always have. You're nice. Don't copy the bullies.

Get thee to the Gryffindor common room where he can't get in!

Never in all of her character development can we imagine JK Rowling explore the idea of a half-naked Neville on the front of a magazine. No wonder she wanted to give him a bit of a ticking off for shocking her. Thankfully he remembered his polite ways and apologised.