How we judge and evaluate characters
A lot of people seem to judge a film's protagonist character simply on what they are like at the beginning of the film, that seems rather unfair I think.
In the Moana v Merida thread, a few people are being harsh on Merida because they think she is silly and selfish for only thinking of herself, not wanting to do what is expected of her and endangering the life of her mother in the process. And yes that is true to a point, but is she still that exact same character by the end of the film? I don't think so.
It's important to realise that a character arc is dynamic and changing, that means we should judge a character not simply on a first impression but also consider how they react to the events in the story, how they develop and what they learn by the end.