It's slightly more amusing; that's because Elly inadvertantly gives Mike lots of nifty ideas.
Panel 1: Mike tells Elly that her story was cool; she asks him if he liked it as a means to figuring out why he likes it.
Panel 2: He likes it because he never knew that she shoved a potato in the tailpipe of her granddad's car or that she'd boiled a dead racoon on Marian's stove.
Panel 3: It impresses him that she did stuff she'd NEVER let him do; that's because he's a kid and doesn't realize that Elly has no intention of letting him sink to her level of deviant behavior.
Panel 4: Inspired by tales of juvenile asshattery and mindless vandalism, he smiles as he walks away and plans his own atrocities. It should be noted that his body has contorted so that his gluteus maximus faces forward.
Panel 5: A freaked-out John tells a bug-eyed Elly that this is why people wait until their kids are grown to write their memoirs.
Summary: This is yet another example of Straw Man John having a good point we're not supposed to really agree with; he can foresee that Mike will answer any attempt Elly might make to reign in his destructive tendencies by pointing out that she was as bad or worse as a child. He is not supposed to, however; that's because Lynn seems to believe that Mike is not playing fair by making that inevitable connection.