I'm sorry but u have to have a really strong heart to not turn into someone bitter and angry after what elsa did to Anna from Anna's perspective...to Anna she was just ignored n unacknowledged by her sister for no reason...other people would have just given up or worse turned against elsa out of anger and sadness...look what hans turned into from lack of love and attention from his siblings!
Anna is incredibly kind and optimistic, enough to put her up top with girls like Cinderella and Snow White!