I can so see her sitting at the window and twirling that little bit of brown hair around her fingers whilst thinking about escaping and if the world really is as bad as "mother" makes it out to be...
It's kind of a spoiler so you don't see it in the publicity arts and even after seeing the film 100x times it often slips your mind... I don't put it into every drawing I make of Rapunzel either but sometimes it's a nice little detail to throw in there.