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.
Chad's wall of banned has Zac Efron on it for reasons unknown. Fast forward to Starstruck, Christopher Wilde (Sterling Knight)'s girlfriend dumps him for Zac offscreen. Not to mention in "17 Again", where Zac play's Sterling Knight's dad.
Ho Yay: Nico and Grady, bordering on Ambiguously Gay. For example, one episode had Grady and Sonny pretending to date whilst Nico and Tawni pulled a prank. Later when they meet up they both ask "Was she better then me?" That's right Nico was asking if Sonny was a better girlfriend then him.
Tia: And welcome back to Tia. I'm here with Hollywood's it couple du jour. Sonny Munroe and Chad Dylan Cooper, or as I've just decided to call you, Channy. Sonny: Oh, that's cute! Channy, I like that. Chad: Oh, we've got our own mashup name.
Replacement Scrappy: The De Fictionalization of Mackenzie Falls led to the previous actors being dropped. The most noticeable of these is the ditzy Portlyn, Chad's onscreen love interest (who the fandom took to shipping with Nico). Her replacement Penelope didn't sit well with fans. Though above is another reason.
Shipping: Channy (Chad/Sonny) as the Fan-Preferred Couple by a huge margin. Next biggest is Tawni/Sonny. Occasionally other ships are teased, such as Sonny/Nico in the pilot (with no Chad), and Sonny/Grady in a more recent one.