In the first game, Cielo gets out of confinement by throwing a cat at the guard.
Cielo is pretty good at providing these.
Ya can't be reasonin' with god, bro! Maybe I should show him some jammin' Latin rhythm, oh yeah baby, dig it!
Cielo's reaction to when he sees Argilla dressing as Sera is priceless.
Cielo: Okay... Dis seriously won't work.
Gale: Why is that?
Cielo: Obviously! Sera isn't dis tall, her hair is way different and her arms ain't dat thick— *Smack* Oow.
Argilla: Well, excuse me.
Mick The Slug trying to escape, only to run into the Embryon before Heat repeats his line about tearing him apart.
Setting up for the repeated threat, Argilla prompts Serph by asking, "What was it Heat said, again?" Your options are: "I think it was something like..." (prompting Heat yourself) or "I don't remember." Pick the second one?
Heat (to Serph): You really suck. (to Mick) I'm gonna tear you apart, you fat freak!
Titania threatening Serph when revisiting Coordinate 136.
Titania: I'll ram this Sugar Key so far up your ass that it can watch me kick the crap out of you!
Cielo suggesting that Sera uses jammin' Latin rhythm to quell God's anger, complete with a little dance. Fred's facepalming in the background really makes it.
The look on Roland's face when he gets called "the clever one" by Argilla.
The mantra named Wikipedia
The Hip Hop / Hee Hoo Brothers. Full stop.
Some of the NPC dialogue has its moments. In the second game, a member of the Lokapala tells Serph not to look down on him, he went to college! One of Serph's possible responses is "Which Tribe is that?" and the guy thinks Serph is mocking him. This is a Call Back to a minor conversation in the first game where an NPC remembers once going to a tribe called "School".
Speaking of which, there are many minor conversations with the party members and NP Cs if you revisit locations you've already completed at various points in the story, and several are hilarious. Such as the party being weirded-out by a random ex-Maribelle NPC who wants Serph to devour her, the "School Tribe" discussion, or this conversation after the first cutscene at the New Embryon Base.