(Strip Number 270, Original Publication Date, 8 June 1982)
Panel 1: We start off with Lizzie and Mike being forced to share one another's company; after having picked up one of Mike's Hot Wheels, she starts screaming "My car!!" when Mike tries to retrieve it. He then makes the mistake of insisting that it's his car.
Panel 2: He then really screws up by simply grabbing it out of her hand; this, of course, causes her to yell "WAAAAAAAAAAAAAAAAAAAAHHHHH!!!!!" at the top of her lungs.
Panel 3: Realizing that Elly will always stick up for the pain in the neck in the ruffled overalls no matter what, he frowns a Gorey-eyed frown of frustration and hands it to her while snarling "Here you go, you little fink."
Panel 4: He's then baffled by her simply tossing it over her shoulder.
Summary: He shouldn't be; that's because Lizzie has the need to be thought of as getting away with something encoded into her DNA; the same impulse that caused Lynn to get bored with things simply given to her when it was more fun to be sneaky caused Lizzie to do this. At least that's what I expect the notes to say if they aren't about how confusing Katie's behavior was.