When Miss Andrew first appears, in Mary Poppins Comes Back, she criticizes everyone and everything in the Banks household. After Miss Andrew calls Mary Poppins an unreliable nanny, Mary Poppins frees Miss Andrew's pet lark from captivity, then allows him to lock her in the birdcage. The lark proceeds to lift the cage and Miss Andrew up into the air, then let both of them fall to the ground. Miss Andrew becomes so traumatized, she takes the next taxi out of Cherry Tree Lane.
In Mary Poppins Opens the Door, Mary Poppins returns to the Banks children by bursting out of a firecracker lit on Guy Fawkes' Day.
Every song the Sherman Brothers wrote for the film, particularly "Feed The Birds", which became Walt Disney's favorite song.
Try to find someone born after 1960 who doesn't at least start smiling and nodding, if not outright singing along, when you launch into "Let's Go Fly A Kite". Go on. We'll wait.
Michael Banks has a few moments: When he stands up to the president of Fidelity Fiduciary Bank, and when the children are running through the docks and encounter Bert, he immediately tries to protect Jane before they realize who they've run into.
When Admiral Boom engages in a fireworks war with the 'hottentot' chimneysweeps. The chimneysweeps duck left and right, but Mary Poppins just strolls calmly back to the Banks' chimney, as if daring the fireworks to hit her.
And then, when a firework zooms towards Bert, he uses his sweep as a bat, and hits the firework right back at Admiral Boom.
Mary Poppins pulling an excellent Batman Gambit on Mr Banks, first by getting him to agree to take the children to the bank, and telling the children about the bird woman, so they'd want to feed the birds, and the resulting events at the bank result in Mr Banks first getting fired, then reconnecting with his children.