The Mad Hatter: There is a place. Like no place on Earth. A land full of wonder, mystery, and danger! Some say to survive it: You need to be as mad as a hatter. Which luckily I am.
When Alice leaves to think over Hamish's proposal and chases after the White Rabbit, her shoes have become flats, but after her fall, when she stands up to check the doorknobs, her shoes have heels once again.
Alice's impending battle on the "frabjous day" with a creature referred to as a "Jabberwocky" is a central plot point, and refers to Lewis Carroll's famous poem "Jabberwocky," from which other characters in the film, such as the Jubjub bird and Bandersnatch, are derived. However, the titular creature of the poem "Jabberwocky" was NOT a Jabberwocky, but a Jabberwock. For whatever reason, the writers of the film chose to call it by the [admittedly similar] title of the poem instead of the actual name of the creature. (For the full text of the poem, see http://www.jabberwocky.com/carroll/jabber/jabberwocky.html).