These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
"One More Time", a licensed song used in "Radio Rhythm" (and coincidentally was also used in a Merrie Melodies short, called "One More Time" in 1931).
Dork Age: Any of his non-Disney Shorts. The early Lantz shorts and the batch that Bill Nolan directed by himself do have their fans (largely due to their Mind Screw qualities), but few consider them to be up there with the original Disney shorts.
Ear Worm: The "My, My, Yes, Yes!" number from "Radio Rhythm".
Genius Bonus: In the Lantz Oswald short "Sky Larks", Oswald and his friend visit the planet Mars, where every living thing on the planet is a weapon. This seems like surreal silliness for it's own sake, until you realize it's a nod to the Roman God Mars, who is associated with war.
The montage midway through "Confidence" when Oswald is trying to find help for his ailing farm, amid the American economy going into shambles, while screaming "DOCTOR!"
Seasonal Rot: While not as liked at the silent Disney shorts, the Lantz Oswalds from the early 30's are still perfectly enjoyable, creatively animated cartoons. Unfortunately, by the mid to late 30's, the shorts took a substantial downslide in entertainment when it abandoned it's humorous and surreal roots in favor of more cutesy, Disney like material.
This also applies to the post-Disney Charles Mintz shorts, which are universally considered inferior to Disney's Oswald shorts.
Tastes Like Diabetes: A common criticism of the "White Oswald" shorts that Lantz started to produce from 1935 onward. Most of the Lantz entries after the first year or so tended to be very cutesy, but it became overwhelming after the redesign.
Tearjerker: After Walt Disney and Ub Iwerks stopped working on the character, he would continue to decline in popularity until he was almost completely forgotten. Look at what happens to him in Epic Mickey after that.