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.
Awesome Music: Many people who grew up watching the shorts consider many of the songs to be this. So much so that quite a number of them have been covered by popular artists and bands (as mentioned before, De La Soul sampled "Three Is The Magic Number" for their song "The Magic Number" off their 1989 album, Three Feet High and Rising). A tribute album was released in 1996, Schoolhouse Rock Rocks, which featured 15 cover tracks (plus the original intro) by artists such as Ween, Blind Melon, Moby, Better Than Ezra, Biz Markie, and The Lemonheads.
Dork Age: Depending on who you ask, any Schoolhouse Rock songs made in 1993 or later can count as part of this, though there's a fairly strong contingent of fans for whom the only tolerable Money Rock song is either "Dollars and Sense" or "Tyrannosaurus Debt."
Ear Worm: The entire point of the project, and as noted they succeeded brilliantly.
Genius Bonus: In "Unpack Your Adjectives", the bulky guy proves he's the brainy one by rattling off a definite integral, a type of formula you don't even see until after several weeks of calculus. It's completely accurate, and even gets simplified. Doubles as a Freeze-Frame Bonus and an aversion of E = MC Hammer. Even better in that it's an advanced math concept in a Grammar Rock song.
Although the 13 colonies are added in random order in "The Preamble", the following states are added in the right order.(Except for West Virginia, which is never part of Virginia in the map, probably because Virginia would look weird if its shape changed.)
On the Hilarious side of the spectrum, one of the characters in "Walking on Wall Street", the kid selling newspapers, with his orange hoodie, round face, and wild red hair looks like a younger version of Wreck-It Ralph.
On the Harsher side, there's "Tyrannosaurus Debt" which gets harder and harder to listen to as the national debt rises year after year.
"Figure Eight" can also come off as depressing and cold (as per the winter setting of the short).
"If you skate/Upon thin ice/You'd be wise/If you thought twice/Before you made another single move..." Those lines are accompanied by a boy skating a figure eight on thin ice, falling through and jumping back out nearly frozen to death.
The aliens and space setting in "Little Twelvetoes".
"Rufus Xaiver Sasparilla". Something about those bizarre body portions and Slasher Smile...
Painful Rhyme: "Interplanet Janet" uses girl:world; "A Victim of Gravity" uses cup:up.
cup:up is only bad compared to the melody, but "Sufferin' til Suffrage" has the extremely painful rhyme suffrage:what age in the chorus.
The intro rhymes "history" with "mystery", which WOULDN'T be a painful rhyme, if it weren't for the fact that, in order to fit the meter, "history" is pronounced as "hiSTORy", while "mystery" is spoken like normal.
Values Dissonance: Some ideas about American history and culture that were popular around the Bicentennial, like Manifest Destiny ("Elbow Room") and assimilation ("Great American Melting Pot"), have since fallen out of favor and/or have been picked apart by political correctness.
Values Resonance: The pleas for conserving natural resources in "The Energy Blues" are as relevant now in the 20-teens as they were in the 1970s (possibly because the need to do so hasn't faded from the public consciousness).
The "Tyrannosaurus Debt" song isn't that dated, considering concern about the economy and the U.S. owing money to other nations (with China being the biggest).
The Woobie: That "sad scrap of paper", the Bill in "I'm Just a Bill". One suspects that Congress passed him and the President signed him just to Throw the Dog a Bone.