- Ear Worm: The theme song and just about every other song for that matter.
- Genius Bonus: In the background, you can usually see clouds shaped like infinity symbols and erased formulas that most 6-7 year olds wouldn't even have heard of.
- In "The Arch Villain Problem," when Arch turns something into an arch, the resulting puff effect says "Y = -X^2," the formula for an upside-down parabola, which is an arch.
- Moe: Just about everyone looks cute.
- Most Wonderful Sound: Ramone's singing voice.
- Nightmare Fuel: You'd think a light and cheery show wouldn't need this trope, right? Wrong! In "The Friday the 13th Problem," Richard's fear of the eponymous number seems to invoke this trope. The song he sings in the episode doesn't help at all, showing disturbing imagery such as skeletons, a ghost (good thing it was just a squirrel), and a cloudy skull in the clouds.
- Periphery Demographic: Among older math geeks, as well as people who enjoy its brand of humor.
- Squick: A few moments in "The Potty Problem". Kind of a given, since the premise is that an alien does his "business" on the floor because there are no toilets on his planet.
- When he poops on the floor we never see the poop, but we do see stink lines and apparently it smells really bad. At one point, some flowers even wilt when he does it.
- At one point, Peg writes down a number on a piece of toilet paper and then Big Mouth uses it and flushes it down the toilet. He'd just pooped twice, so he probably only went Number One, but still.
- Tastes Like Diabetes: Well, some people think all kids' cartoons are too sugary.
YMMV / Peg + Cat