Mina's enthusiastic but incompetent attempt at cooking in episode 5, and her getting mad at eggs breaking so easily. Then there's her miming "taste testing". As a vampire, she has no sense of taste and so she is oblivious to the fact that she's incompetent.
The flashback in Vol. 7 to Akira and Angie's ritual ordeal, and Sanin's comment about why mankind invented underpants.
"It's not modesty or anything like that. It's just...It gets in the way, y'know? Bouncin' all over when you run..."
Yuki's and Mina's planning for the BL novel, only for Akira, standing right behind them, to hear the whole thing. It's made even funnier in that Akira is the unwitting model for the main character.
In volume 12 at the end of Mina's rescue, once Akira has successfully rescued and has Mina away from Rozenmann and his retainers Akira whispers into Mina's ear. Cue Mina in the next pannel flipping them the bird. What really makes it A CMOF is the exchange shotly there after
Mina: "So, What did that gesture mean?" Akira: "Uh... I think you're better off not knowing."
An old man that has been turned by a group of homeless vampires ends up at a Tokyo hospital and lunges at Seiji when he turns his back. Seiji looks shocked at being bitten, then there is a Beat Panel of Seiji looking irritated as he remebers the man was so old when he was turned he has no teeth left while the vampire gums him to no effect
Nearly every volume ends with a 4koma-style following the antics of three of Mina's maids. They're hilarious, and considering the dark note many of the story arcs end on, a welcome change of pace.