- Awesome Art: The vibrant, lushly-painted backgrounds are gorgeous, while the character designs pay homage to the work of Beano artist Leo Baxendale as well as classic Nickelodeon characters.
- Base-Breaking Character: The title character himself. Several viewers have criticized the character for his unappealing design, bland nasally voice, poorly-adapted personality, and in some episodes he acts like a total whiny jerk who gets away with everything. While some think that he gets crammed in every episode that does involve more with him rather than Zeke, Marsha, and most of the side characters, to the point where they rarely appear in almost most of the episodes, aside from appearing either minor or supporting role. (Judy has gotten this the worst of them all.) However, some people have grown on the character, no matter how bad his design or voice is, especially after the Season 1 finale.
- Ear Worm: The show's theme song will be stuck in your head for days!
- The song that plays during the end credits, "Catch Me If You Can", is pretty catchy too!
- "When you're in lovvvvvvvve..."
- RATS MAKE EVERYTHING BETTER, RATS MAKE EVERYTHING GOOD!
- Hey hey hey hey, what's with these kids today?
- Ensemble Dark Horse: The Subterranea-Tania characters are very well-liked way more than the title character himself, considering how unique and diverse they are in terms of appearance and personality.
- The biggest one would have to be the green swamp girl Judy, due to having an adorable and appealing design. She only ever appeared as a one-off character in the series in the appropriately named episode "Hey Judy". (She also made 3 smaller appearances in the series.)
- Moe: Marsha.
- Also Judy. She is arguably the most adorable thing to come out of the show.
- Never Live It Down: "WE ARE NOT YOUR FRIENDS, BILLY DILLEY!!! GO AWAY FOREVER!!!!"
- It's Short, So It Sucks!: Mostly the series itself, by the length, it aired only 13 episodes and lasted only 2 weeks for most of its run.
- Ron the Death Eater: The title character himself falls into this. While he is a Ditzy Genius and The Klutz, many people are making him out to look like a complete sociopath who likes to ruin things for fun and abuses his friends for his own amusement. (Which he never does in the actual show.) He's just a good natured kid with bouts of selfishness and naivety.
- Spiritual Successor:
- To Nickelodeon's Sanjay and Craig. It helps that a few crew members worked on Billy Dilley, after production of "Booyah for Bollywood" finished.
- A more accurate comparison would be SpongeBob SquarePants (which Aaron Springer previously worked on), Chowder, The Marvelous Misadventures of Flapjack, or The 7D.
- It's also the third in Disney's unofficial "Summer Vacation" trilogy, following Phineas and Ferb and Gravity Falls (which each premiered five years apart).
- So Okay, It's Average: The show itself, isn't considered just bad or good, but rather just basic to most, despite of the main character having to be more or less favorable, most of those who watch the show tend to be more interested in Zeke, Marsha, and pretty much all of the Subterranea-Tania characters. However, in recent years people have started to look past the show's flaws and come to appreciate its' lighthearted, whimisical tone, even deducing that it Needs More Love.
- They Copied It, So It Sucks!: The design and voice of Billy Dilley has received this reaction from viewers, who have compared it unfavourably to Uncle Grandpa and Clarence.
- They Wasted a Perfectly Good Character: Judy. She hardly got any spotlight and development and only ever made four appearances throughout Season 1. Her official debut episode ("Hey Judy") was her only major spotlight role, her second and third appearances ("The Mushroom Prince"note and "Rat's Entertainment!") were non-speaking cameos, and her last appearance ("The Battle for Subterranea-Tania") was a more semi-recurring role where she only had a few lines and didn't get too much spotlight here. The series' small fanbase expressed disappointment in how underused she was compared to most other side characters. It's gotten to the point where she the mascot of this trope. (Which is shared with Sam Lastnamè) Aaron Springer however declared that she would've gotten far more screentime had the show got picked up for a second season.
- Win the Crowd: A lot of people got very excited when it was announced Aaron Springer, acclaimed for his work on Spongebob and Samurai Jack, was finally getting his own show, having had many close chances in the past with Periwinkle Around the World and Korgoth Of Barbaria.
YMMV / Billy Dilley's Super Duper Subterranean Summer