The Wonderful Wizard of Oz/Fridge

Fridge Brilliance

 * The Wizard gives the Lion liquid courage.
 * Scarecrow's incorrect quote after receiving his diploma. While often regarded as a goof, this could have been intentional, subtly implying the brain the Wizard gave Scarecrow was fake - since as is established, Dorothy, and by extension the whole group, had all along had what they were looking for, just not been aware of it.
 * They have to climb over a large wall to get to a land where everything and everybody is made of china. A great wall, one might even say.

Fridge Logic

 * If Oz is real but is surrounded by the impassable Deadly Desert, how did enough people reach it to establish a viable population, let alone a civilization of five distinct nations and innumerable smaller cultures?
 * As I recall, Oz used to be connected to the other magical lands. A passing fairy queen made the impassable deserts and isolated Oz from the outside and enchanted the land. They may have been already people living there. The four nations came about when the last King of Oz disappeared along with his daughter and four Wicked Witches carved up Oz among themselves. Later two of the four Wicked Witches, North and the South, were overthrown by Glinda and an unnamed Good Witch. As to the fifth nation (The Emerald City), that was founded by the Wizard after he came to Oz.
 * Wicked (the book) gave a simpler, Hand Wave-ish explanation: the desert isn't really deadly; that's just a bit of political propaganda intended to discourage foreigners from intruding into Oz.
 * If the witch melts with water, how does that dirty woman take a bath?
 * Dry cleaning.
 * Actually, that's more or less what Wicked said; she rubs oils into her skin.
 * She's a witch, maybe she just magics herself clean?
 * If there is No Death in Oz what does Munchkinland need with a coroner?
 * Well, that's one more Munchkin who escapes unemployment -- possibly the fact that his job is essentially pointless is less important than the fact that he has a job. There are a lot of "jobs" like this in Oz canon; they're of no practical use to anyone except to let people feel they actually have something to do.
 * My recollection is that "No Death in Oz" is only true in the books, and the coroner only appears in the film, so there's no contradiction.
 * This video asks why the question: if witches can be killed by the impact of a falling house, why not the impact of bullets?
 * If the Tin Man is really made out of tin, then he can't possibly rust, as tin doesn't rust. In fact, it resists corrosion so well that it is often plated on to other metals to prevent them from corroding.
 * There's always the option of his joints being of a different metal than his body. It's perfectly possible that while his main body parts (chest, arms, head etc) are made of tin, the stuff that keeps him together (bolts, joints, etc) are made of something else, like iron.