Kana is seriously into the moment when she and Daikichi are ... you know ... and she floats towards the ceiling clutching Daikichi. When she, ahem, finishes, she gets a bit insubstantial, leaving Daikichi unsupported several feet above the ground. Gravity Ensues.
The scene when Inagawa "reaches out to touch the supernatural."
Utako counting the number of hands washing her in the shower.
"1.. 2... 3... 4?!"
Kana's retaliation for Daikichi drawing all over the image of her face on the peace wall, when she's in it for a significant time after an argument. It wouldn't be funny, except for the situation and the fact that when you look at her face on the wall behind him when he wakes up with the bloody handprints, she's sticking her tongue out and audibly raspberrying him.
The book signing in chapter 20, directly related to previous chapter 5 example.
The whole first part of chapter 4 (after the teaser/title page).
She's pretty excited about getting to drink beer again after so many years. And even notices they changed the label. As she goes on to drink Daikuchi further into the poorhouse in chapter 1.