While the scene sheds a light on why Jack is battling so many demons — the Vietnam War was infamously traumatising for the service people who came back home — it also reveals the vet has been hiding a major truth about himself for at least a decade. In season 1 finale "Moonshadow," we meet one of the youngest versions of Jack we’ve ever seen. Gone is the dad bod and bushy moustache; in their place is a floppy-haired young man in the mid-70s. In this time, Jack is a down-on-his-luck mechanic happily accepting every drop of cash he can get from a job. As usual, he’s his signature sweet, well-meaning self. When Jack finishes working on an elderly widow’s car, she can only give him a $5 bill for his services. He's still more than appreciative. "How did you come back from Vietnam so nice? Seems like most of the boys lose their damn minds over there," Mrs. Peabody (Debra Mooney) asks her boyishly handsome repairman. Jack responds, "I was just a mechanic. You know, maybe we had it a little easier over there."