Personally I love how the "parental disagreement" is shown. Quite risky for it's time I guess. Like "OK, who's kid is this!? What do you have to tell me?" Also the visualization of the little "duckling's" emotions are quite heartwarming.
Not to forget the quack-quack-quack-quack-quack-HONK! that makes me keel over with laughter every time :D