Panel 1: Mike's reaction to John's breezy decree that he's old enough to be put to work is to react in stunned disbelief. As he tries to explain to John, he doesn't want a job because this is Summer and it's a holiday. He should know better than that but he does not.
Panel 2: This is because he's forgotten that John has been calling him a lazy, entitled and selfish little boy who doesn't know the value of actual work since after they brought him home from the hospital, Mike didn't immediately jump up and start vacuuming out the car and is baffled when Train Man reminds him of this when he says that he was Mike's age, he was mowing lawns, pumping gas and delivering groceries.
Reason: he doesn't understand that not everyone is hampered by the delusion that the most enviable state is being a mewling puking infant because no one yells at you all the time.
Panel 3: He was motivated! He found things to do! He didn't spend all day watching television!
He also didn't have a screaming moron mother who killed the holy living shit out of his curiosity and a massive weeping dick of a father telling him that he owes his parents every cent spent raising him making deciding things look like the worst thing ever.
Panel 4: Mike channels Lindy when she absorbed that speech from her parents by being all surly and thought-bubbling "That's because it hadn't been invented yet."
Summary: It's always been a source of irritation that John doesn't really understand that most people think that having children to breed a workforce for one's self is a garbage move. I wonder where Lynn got this idea and I wonder if she's got Katie thinking the same evil and petty thing.