Light: I believe we came here to investigate the supposedly haunted house, not our mental issues.
L: ... However many they may be.
Light and L getting into an extended metaphor, where L loves cake and would cherish anybody who brought him one, but if Matt is cake then Mello would eat him, but the point of the metaphor is not that Mello would cherish Matt, but Mello isn't a cannibal... unless Matt is covered with chocolate syrup?
L: I am no longer sure what we're talking about.
L's incredibly childish rivalry with Beyond Birthday.
Light: Next you're going to start sticking out your tongu- just like that! L, I saw that!
Misa visits the Whammy House, and Near announces that Mello is seducing Light while in drag. Every single girl immediately rushes to the windows.
Matt: Don't even try to explain! It's over between us, you hear me – over! And to steal the boyfriend of your own brother – you really are the lowest! Shame on you!
Mello: ... What has he eaten?
L: Apparently, you have seduced my boyfriend. According to my knowledge of social relationships, we are not on speaking terms for now.
Mello: ... WHAT?
Almost anything with Near is this, with a side order of adorable.
Near: I want Chocopops. And I grew tired of waiting for you two to finish your relationship drama, so I interrupted you. You may proceed once I have had my bowl of Chocopops.
L: You mean Mello's Chocopops.
Near: Yes, that's why I want them.
Near: Yes, I'm planning on infiltrating among the ghosts and becoming their king.