I came to this thread thinking "wow, 4 pages, lots of people liked it" just to find out half of the thread was a discussion about skylines.
Anyway, I loved the movie and everything but for a whole hour I thought Jack was a girl, I don't know if it was because of the hair, but he really looked like a girl. I was so certain of it I actually started elaborating theories about why she was being called a he, I though Joy was pretending that he was a boy so that Old Nick wouldn't rape him, and that's why she would never let him go near Jack. But then even the cops were saying "he" and "boy" and I realized, in the middle of the movie, that he really was a boy. It was one of the strangest feelings ever.