Archive Panic: The original theatrical cartoons combined amount to 469 shorts total (not including shorts initially released as part of a bigger feature, such as the shorts in The Reluctant Dragon, Saludos Amigos, The Three Caballeros and the 40's Disney package features) and that number shoots up to 562 if you include all of the silent Disney films (the Newman Laugh-O-Grams, the Alice Comedies and Oswald the Lucky Rabbit)note although only around 50 of the 93 silent Disney films survive, are available or are known to exist—to watch all of them in chronological order would take around 66 hours and 30 minutes, or close to three days without sleep. And that's not counting post-Golden Age shorts, TV shows and feature animation appearances of the characters. And lets not even get started on the absolutely monstrous number of comics these characters have appeared in, especially the Donald Duck comics.
Toby Tortoise Returns is an oddball in the Silly Symphonies lineup-wheras most, if not all of those shorts were either sweet, sentimental and naturalistic, this short has much more in common with a Warner Bros. cartoon, complete with full cartoony, fast paced slapstick comedy.
Mickey Mouse's "Runaway Brain" from the 90's, which was the first (but certainly notthe last) attempt at returning Mickey to his adventureous, edgier roots. Whether it succeeded or not is up for debate.
The later Donald Duck shorts from the '50s and onward show how desperate the writers were to come up with new ideas-one short has Donald become so obsessed with obtaining honey that he dresses up as a bee to steal honey from an actual hive, instead of just going to the store and buying some honey in a jar like any sane man duck would do.
There's also the Silly Symphonies short "Mother Goose Goes Hollywood", which is yet another pure comedy Disney short, featuring caricatures of Golden Age Hollywood celebrities in the roles of classic fairy tale characters. The opening logo is even a parody of the MGM Lion-except with a goose (albeit one that roars like a lion)!
Wilfred Jackson disliked the early Mickey Mouse short "The Castaway" and upon its failure vowed to never make another picture that didn't feel like a Disney film again.
According to "Of Mice and Magic", some of the Donald Duck staff grew to dislike the character and how formula driven his shorts became over time. One of the directors, veteran Jack Hannah (no relation to Hanna-Barbera) even complained "I got so damned tired of that duck's voice. I just could not stand having to work with it all the time."
It should be noted, however, that Don's most formulaic period came precisely when Hannah took over as the sole director of the series and apparently made his life goal to fill the duck's filmography with repetitive stories. Really, count how many cartoons that pit Donald against vermin -where he's Out of Focus and suffers from severe Flanderization- emerged on this time as opposed to the past. There were some nice exceptions here and there, especially at the beginning of Hannah's tenure, but for the most part the Duck owes much of his personality loss to these pictures.
According to Neal Gabler in his book "Walt Disney and the Triumph of the American Imagination", Walt "absolutely hated the Goofy cartoons, threatening constantly to terminate them before relenting, largely to provide work for his animators."
No Smoking becomes this due to Walt Disney's death from lung cancer, especially the gag where a skywriter spells out "Smoke Lookys" (Lucky Strike was Walt's preferred brand). Tellingly, one TV edit of the cartoon has a new ending where Goofy really does give up smoking.
Vanilla Protagonist: There's a startlingly low amount of shorts focused on Mickey in the 40s and 50s, even those categorised as his cartoon, his more laid back Every Man persona making him rather dull compared to more proactive co stars such as Donald or Pluto.