Seems like there’s a common them to almost every Disney movie, children rebelling against their parents.
them=theme
I never thought about that until you mentioned it.
Perhaps, but in Pollyanna the child in question pays a pretty heavy price for rebelling.
I would agree that there's a common theme of children undergoing the process of discovering that they have minds of their own and can explore the world in their own ways, but that's just life.
I suppose one could argue that Tom Sawyer and Huckleberry Finn are about children rebelling against authority, also.
In Mary Poppins, the children discover that their father is not the perfect tower of strength they had thought he was; we see Mr. Banks as a man who is reluctantly but resignedly taking on the pressures and responsibilities of adulthood and fatherhood, but within whom still lives a boy, who wishes he could enjoy his own children as playmates for a time, but cannot, due to the need to earn a living and keep them in the manner to which they have become accustomed.
Theres frequently a dead mother in there, too.
Saving Mr. Banks is a very good account of how Mary Poppins was made in spite of the author P.L. Travers' objections to Disney and her own deep seeded issues with a failed father. In her case an alcoholic bank manager, fired from his job out in an isolated country town in Australia.