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.
Big Lipped Alligator Moment: Sonny briefly hangs out with some of Julian's friends in the schoolyard, slyly questioning them to try to find out if they're "smoking dope" or "drinking rum." They aren't. Unusual as this scene is the the punchline from a previous scene. Layla mentionned that she heard one of the biggest influences on a child is who s/he hangs out with and the such, and then makes a joke about how she hopes Julian isn't hanging around drugheads at school. She sees his reaction, assuming it's concern, but the ensuing BLAM reveals it might be shame.
Designated Villain: Deliberately invoked with Arthur Brooks. He's just doing his job - and is completely justified in doing so since Sonny lied to him - but in the context of the film he comes off as somewhat mean.
Also, when Sonny shows up at the party for Kevin near the beginning of the film, all the other guests mistake him for Kevin and shout "Surprise!" at him (and are therefore much less enthused when the real Kevin arrives a minute later, causing Corinne to complain: "We wasted the good surprise on you! and run into the bathroom to cry). After watching the film a few times, you start to realize that Sonny and Kevin do look a great deal alike except for their hairstyles and Sonny's slightly darker complexion, and this becomes Fridge Brilliance when you connect it to Sonny's scheme later in the film to impersonate Kevin in order to gain custody of Julian (and, indeed, the physical similarity just might have been the reason why Sonny thought the ruse would work in the first place).
Hollywood Pudgy: Sonny is described both by Corinne and by himself as "fat." We never see Sonny without his clothes on, and he's not likely to be in very good shape due to his sedentary lifestyle, but to call him "fat" is an exaggeration.
Never Live It Down: Sonny gleefully brings up that Corinne used to work at Hooters whenever he's around her, much to her chagrin.
Not limited to Sonny. One of their friends pretty much makes her (and needlessly so) admit in court, during testimony, that she used to work there while she was attending medical school.
Played straight with Arthur Brooks. The social services agent who brings suit against Sonny for fraudulence and kidnapping appears to be heartless when he drags a frightened, begging Julian out of Sonny's apartment. However, he sincerely has Julian's best interests at heart and was right to bring Sonny to trial. And when it appears that he is going to lose his case, instead of becoming bitter he is so moved by Sonny's testimony that he immediately takes out a cell phone and calls his own father (along with most of the rest of the cast).
Similarly, the characters are aghast when the judge rules that Sonny is to be jailed for "kidnapping" Julian...which is more or less what he actually did.