(Strip Number 878, Original Publication Date, 25 June 1985)
Panel 1: As he mixes the lemonade, Mike channels Elly by having the closed-eyed superior frown spot-welded onto his face when he tells Lizzie that he gets to do so 'cause he's better at making stuff.
Panel 2: When Lizzie drinks some of it before they can sell it, Mike again acts like Elly by freaking the [boxcar] out and yelling not to do so.
Panel 3: He again turns into Elly by simultaneously grabbing onto the cups and cooler like a starving octopus and walking so quickly that Lizzie can't hope to keep up AND telling her that she's gotta do somethin'cause he's not doin'all the work.
Panel 4: Having observed how close his behaviour is to her own, Elly thought-bubbles "Never go into business with relatives."
Summary: A better punch-line would have her go "Who taught him to act like that?" because it would highlight how unaware Elly is that her children learn how to live by watching her and John.