Awesome Art: The series gets consistent high praise for its eye-popping use of Flash animation, a combination of extremely detailed 2D rigs (basically, every conceivable angle of the characters are pre-drawn) animated frame-by-frame as opposed to tweened, as well as "paperless" traditional hand-drawn animation. There's also the brilliantly lit backgrounds, and unique designs.
Crazy Is Cool: The Duke of Detroit. The climax of his intro episode sums it up: he has a tank that shoots limos. Not as in it shoots at limos, it uses limos as AMMO.
Cult Classic: It's by no means a mainstream Disney show, but it has one dedicated fanbase in sites like Tumblr; certainly helped by the fact that several staff members have Tumblr accounts, which they use to actively talk about the show and share production art.
Designated Hero: In Texas's image spot, he and Mike appear as ones. Mike runs off to play hide and seek note instead of going missing like in the episode in question when the weather machine threatens everything in Motorcity. Texas assaults and beats up the Hockey gang for bothering him while eating note in the actual episode they attacked the burners to get the bounty on their heads, and getting the other gangs in on a high stakes race with the Duke, just to make it more challenging note instead of The Duke doing that through loophole abuse. He also deliberately compromises his shrinking plan for infiltrating Kane co. because he thought it was too good and needed to humor Mike's plan note instead of his plan being to impractical, and Mike's plan being the one used.
The Duke Of Detroit. The days surrounding his premiere episode had a staff-run art contest for him. He was supposed to only appear in 2 episodes, but was so popular he got 6, including a major part in the finale.
Foxy of the Amazons (the one female gang leader in "The Duke of Detroit") has gotten loads of fanart and shipping despite having a grand total of one line in that episode. The fandom was in absolute delight when she was featured prominently in "Julie and the Amazons." Being voiced by Jennifer Hale certainly helps.
Similarly, the leader of the Mama's Boys, Junior, has gotten a sizable fan following.
Jenzen has had a good amount of fanart made of him, despite only appearing in one episode and that not a lot is known about him. Could be because some fans think he's Red as they debuted in the same episode.
Three episodes, "Blond Thunder", "Ride of the Fantasy Vans", and "Fearless" are Chuck centric episodes dedicated to developing the relationship between Mike and Chuck.
Not to mention the intense relationship that Kane and Mike share, as early as episode 1...
Kane: Backstabber! How could you chose this... this... sewer over ME!
Dutch and Texas basically snuggling◊ in episode 6.
Dutch also likes to henpeck Texas as if they were an old married couple, example where this is evident is "The Duke of Detroit" and "Like Father, Like Daughter".
The pilot is even more Ho Yay-full, including this little gem:
Texas: My hands are registered as legal weapons!
"Luv"note Dutch's original name: Your breath should be classified as a legal weapon!
Texas: Well then stop trying to kiss me!
Claire was very impressed by Foxy in "Julie and the Amazons." The whole episode in fact is rich with Julie/Claire Les Yay.
Making variations of Mike's name like: Mike Chicken, Milk Chilton, Bike Chilton, Mike Hilton... the list is way too long.
Giving Mike rabbit ears or even making him into a rabbit due to his cowlicks. And similarly making Chuck into a dog and Julie into a cat.
Periphery Demographic: While it's a hit with its target audience, it's also become incredibly popular with viewers (including females) in their late teens.
Ship Tease: One can argue that it's pretty heavy between Mike and Julie in "A Better Tomorrow."
Spiritual Successor: It's like an all-human variant of Sonic the Hedgehog (SatAM)- Mike is Sonic, Julie is Sally, Chuck is Tails, Dutch is Rotor, Texas is Antoine (though with Bunnie's strength), Jacob is Uncle Chuck, R.O.T.H. is NICOLE, and Kane is Robotnik. And just like that show, Disney screwed it over.