Because my mom enjoyed The Waltons, Bird and I occasionally ended up watching her DVDs of the eponymous family and their neighbors on Walton’s Mountain. Usually it was just the early years, the ones before Ma got sent to a sanitarium for tuberculosis (because the actress quit) and Mary Ellen got married. The later episodes just weren’t as good, according to Mom, for multiple reasons. But one day we found The Waltons on TV and decided to watch it. Other than the actors all looking a bit older and dealing with somewhat more dramatic issues, it seemed pretty normal. There was a stranger living with the Waltons now, but we figured he was a cousin or something.
Except everyone kept calling him John Boy. The narrator.
“That’s not John Boy!” we exclaimed. Mom laughed. Apparently the role had been recast between seasons at some point.
We couldn’t believe it. They were just asking us to believe that this was John Boy, the aspiring writer through whose eyes we saw everything on Walton’s Mountain? It was clearly a completely different person.
“Yeah,” said Mom, “one season he went off to fight in the War and when he came back, it was this guy!”
“Wow,” said Bird. “War really changed him.”
Once we recovered from our laughter and agreed never to watch those later seasons again, this experience gave rise to a new phrase in our household. “John Boy” became a verb, meaning “to recast a character without warning or transition and simply ask the audience to go along with it.”
I was home on a break from school one day when Mom and Bird wanted to catch up on the season finale of a show we were currently watching. Bird, who was texting a friend who had already seen the episode, suddenly burst out laughing at her phone.
“They replaced the brother!” she gasped. “Oh my gosh, they John Boy-ed him!”
Sure enough, toward the end of the episode, the family entered their home to find a strange boy leaning against the kitchen table. Gasping, they all embraced him, addressing him by the brother character’s name. Apparently he had been at boarding school (because the old actor was in rehab or something).
“Well,” Bird deadpanned, “John Boy’s home from the War.”
The Grammar Changeling 
Shared memories like this are the glue of family relationships. For the rest of your life you will know that there are at least two other people who will not only intellectually know of this punch line but share the emotional reaction that arose from the three of you all experiencing it originally – and then later as well.
Given that my parents were both in show business, no straight line ever died a natural death, and if someone was so careless as to utter one there would be a land rush to jump on it with the punch line. They weren’t exactly comedy store material – more like someone showing understanding by saying “I see” and someone replying immediately, “Said the blind carpenter as he picked up his hammer and saw..” But there was real comfort and love in the knowledge that a particular straight line would result in the same response every time. Third parties in the room would look puzzled and that was OK because it was always enough that we knew the setup and the punch line and that we had repeated it hundreds of times over a great many years and it was a badge of family. Other people could say it but it would not be the same – just as anyone else who tried to use “John Boy” as code for a casting change would get frogs and crickets in return.
Congrats on presenting your thesis – and remind me to tell you a joke on the topic next time I see you.