Yet there is one thing that I have observed in television and film that is interesting, characters will sometimes act out of character for the sake of the story. Most of the time the audience doesn't even notice that its happened, and most of these characters are human, they are allowed to make mistakes. In fact, making a mistake will often make the characters feel more real and human, because we all know everyone makes mistakes. Often times this is used to create conflict for the character, and to propel the story onward. Here are some examples.
Sleeping Beauty - One of the BEST from the Golden Age at Disney.
Maleficent places a curse on Princess Aurora, saying that "before the sun sets on her sixteenth birthday, she shall prick her finger on the spindle of a spinning wheel, and die!" So in order to protect the princess, the Good Fairies take her into hiding, vowing to keep her from harm until her sixteenth birthday passes and she will be safe. So they do protect her, and they do a damn good job, for on her sixteenth birthday she is fine. The Good Fairies want to throw her a party, completely understandable, but instead of locking her up in her room on the very last day that she is in danger, they send her out into the forest to collect berries!
Seriously Fairies?! You have spent sixteen years protecting this girl and on the very last day you get sloppy and let her run around in the forest unprotected!! Yet if they had just locked her up in her room until the sun set on her sixteenth birthday, there would have been no conflict! She would never have met her prince, she would never have become Sleeping Beauty, and the prince would never have gone on a quest to awaken her! So the Good Fairies HAD to act out of character to create conflict and move the story along its arc.
Avatar: The Last Airbender - One of the BEST Animated Shows Ever.
First of all, this show is riddled with amazing characters that you just don't want to stop watching. And one of my favorites is Momo, Aang's pet flying lemar.