How we cite our quotes: All quotations are from Mary Poppins.
Quote #1
BERT: Let's sit down. You know, begging your pardon, but the one my heart goes out to is your father. There he is, in that cold heartless bank day after day, hammed in by mounds of cold heartless money. I don't like to see any living thing caged up.
Like Freddie Mercury said in "I Want to Break Free" Mr. Banks needs to…break free. But he doesn't know he's in a prison, because it's invisible—the prison of his career and his misguided values. Only when he's fired from the bank does he experience the thrill of freedom.
Quote #2
JANE: Father in a cage?
BERT: They makes cages of all sizes and shapes, you know. Bank-shaped, some of them, carpets and all.
The cage is obviously a metaphor. Mr. Banks isn't in a literal cage, eating food pellets and scurrying around on a metal mesh floor.
Quote #3
BERT: You've got to grind, grind, grind at that grindstone... Though childhood slips like sand through a sieve... And all too soon they've up and grown, and then they've flown... And it's too late for you to give - just that spoonful of sugar to 'elp the medicine go down - medicine go dow-wown, medicine go down.
Bert warns George Banks against getting penned inside his own workaholic habits. He has to add that "spoonful of sugar" to life—i.e. show his natural fatherly warmth to his kids.