The theatre scene. Real children are huge perverts.
Even funnier when you think of Coraline's reaction to it, and how every kid in the audience probably felt the same!
Now think of how you would create the parallel world of a 12-year-old who expects "everything to be better"!
In the book, Coraline writes a story on her father's computer:
THERE WAS A GIRL HER NAME WAS APPLE. SHE USED TO DANCE A LOT. SHE DANCED AND DANCED UNTIL HER FEET TURNED INTO SOSSAJES THE END.
After she defeats the Other Mother, Coraline is visited by the Cat again in her own world, and she asks if he's mad about being thrown at the Other Mother as a last ditch effort. The Cat's expression, in this troper's theater at least, made the whole audience explode with laughter! Probably because you know he can't say how he feels, because he's not in the Other World where he can talk.
In the movie after Coraline finds the hot water tank, right before she marks down the hot water tank, we see "12 disgusting bugs!" written down. Then when she presses a button, it causes a power surge and causes some problems on Dad's computer, making him yell "NOOOOOO!" and Coraline gets an "Oh Crap" expression on her face, before she runs back to the closet, puts a label "DON'T PUSH" back on and then presses the button, causing everything to go back to normal and then she walks out, trying to act like she didn't do anything.