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.
Hilarious in Hindsight: DoorMouse from Team Umizoomi always wears pants that don't have a hole for his tail to stick out. It's not until the episode "Cold Fish" that Dudley complains about these pants.
Ho Yay: Dudley and Keswick even share a "Lady and the Tramp" kiss in "Law and Odor".
There's also the time that Bird Brain shot Dudley with a love ray in "Love Bird".
I Am Not Shazam: Dudley is only referred to as T.U.F.F. Puppy in nickname form by Kitty.
And that's only once and it was said sarcastically.
The Scrappy: One of those rare moments where the main character is considered the most annoying character of the show.
Notasrare as you think, at least from a Nicktoon perspective.
Ship Sinking: In "Dog Tired", when Dudley was in danger of falling asleep forever, the Chief made him dream about marrying Kitty, which Dudley considered a nightmare. That scene could pretty well crush the hopes of Dudley/Kitty fans.
"Love Bird" contains Dudley falling for a bank teller. Let's just say it wasn't received very well by the Kudley fanbase.
"Till Doom Do Us Part" seemed to have been made to solely sink the Dudley/Kitty ship.
"Girlfriend or Foe" features another love interest for Dudley, named Daisy.
Strawman Has a Point: Kitty was pretty much against working with Dudley and tends to still be from time to time. Given what Dudley does from time to time, it isn't unreasonable.
Jerkass Woobie: The Chameleon pretty much lives and breathes this trope. It's played for laughs, as he's supposedly nasty thanks to being depressed about being alone, but half the reason he's alone is because he's such a nasty guy in the first place. It's not played for laughs when he almost gets T.U.F.F and D.O.O.M to destroy each other and the entire city by tricking them into destroying the city/their "bases," sharing an office, and watching as a real estate agent.