Most episodes revolved around the clash between the "uncivilized" hillbilly culture represented by the Clampetts and the "civilized" American culture of the Drysdales. The Clampetts lived as they always had, even in their large, elegant mansion, never abandoning their mountain attire or replacing the old rattletrap truck in which they had moved to California. Although when asked what kind of truck it is, Jethro said 'I think it's a Stutz', it is actually based on a 1921 Oldsmobile. All the Hillbillies were handy with firearms and always seemed to have their weapons close at hand and ready to draw. They continued to grow their own food, and Granny made lye soap and moonshine. The extreme potency of the moonshine liquor and the harshness of the lye soap were running gags throughout the run of the series.
As another running joke, the movie theaters back in the hills were still showing films from the silent movie era and the Hillbillies were unaware of talking pictures or more contemporary movie stars. Granny's favorite actor was Hoot Gibson, but she also had an intense crush on William S. Hart, and the whole Clampett family adored Mary Pickford. Silent movie legend Gloria Swanson made a memorable guest appearance on the show as herself in an episode that featured a comic parody of a silent melodrama. The Clampetts did, however, have a television, on which they watched soap operas and "rasslin'", as well as John Wayne movies, as he was apparently one of the few "talkie" movie stars of whom they were aware. Wayne made a brief cameo as himself after the Clampett mansion was "attacked" by stuntmen dressed as Native Americans.
Pearl and Granny often fought for kitchen supremacy. Pearl once told Granny "a blood cousin trumps a mother-in-law". This underscored a familial disconnect between Jethro and Granny; although they shared no bloodlines, Jethro still called her "Granny" (as did everyone else on the show, including Miss Jane and the Drysdales). Other than their kitchen wars, relations between Granny and Pearl were generally friendly. The second season began with a brief mention of Pearl having moved back to the hills, an ironic departure, as it was Pearl who had urged Jed to move to California. The change came about because actress Bea Benaderet had left the show to star in Petticoat Junction. Mrs. Drysdale soon became Granny's main sparring partner.
Although both Douglas and Baer were well into their twenties when the series started, during the first years of the series, their characters were supposed to be teenagers. Elly May was enrolled in an elite girls' school in the first season, although no further mention was made of her education in later episodes. Jethro was enrolled in a sixth-grade class with much younger students; a few episodes later on, the scripts suggested that he was still in school.
Should Granny or one of her kin feel lonely for the hills, banker Drysdale would bend over backwards to placate the offended subject. Drysdale went so far as to recreate the log cabin the Clampetts had lived in and place it right next to the "cee-ment pond" and the still Granny had installed to make moonshine. Another time Drysdale followed the Clampetts to the "Hills" and bought up the Silver Dollar City "bank" just to make sure he had a controlling interest in the Clampetts' money. One running gag was that when Jed would take money out of his pocket, Drysdale's blood pressure would go up. A similar running joke was that when it seemed the Clampetts would take their money out of his bank, Drysdale's face would turn green. A variation of the joke of Drysdale's face changing color is in one episode when, after being given some of Granny's "Tennessee Tranquilizer" (moonshine), Drysdale's face turns red.
Another frequent source of humor dealt with Jethro's endless career search, which included such diverse vocations as soda jerk, brain surgeon, Hollywood celebrity, and secret "double naught" agent/spy. Jethro coveted movie star fame and relished becoming a "playboy" like Elly's beau Dash Riprock. Jethro's stupidity usually caused such career attempts to fail spectacularly, as when he decided to open a "topless" restaurant ("The Happy Gizzard"), where the waiters and waitresses were hatless. The one time in the series when Jethro almost succeeded as a "Hollywood celebrity" was when "Cousin Roy" (Roy Clark) tried to get Jethro to back him up as a country singer in Hollywood; Jethro refused and failed as usual. Jethro did have one success, of sorts. When he rescued a Bird Watchers girl troop who fell into the "cement pond" (they were attacked by ants), Jethro got a "lifesaving badge".
Misunderstandings were a general source of humor in the program, such as when the Clampetts did not understand something they had never encountered before (such as a water faucet), or when various city dwellers could not comprehend something the Clampetts were talking about. A group of businessmen overheard Jed talking about "crawdads" and concluded he was discussing a new type of military vehicle, in which they wanted to invest. Conversely, when Jed muses to Mr. Brewster about whether he can afford to move to Beverly Hills, Brewster responds with, "Why, Mr. Clampett, with your money, you could afford the Taj Mahal", to which Jed rejoins, "I'll take it!" When Brewster insists he was making a joke; Jed allows that he can go right ahead. Brewster: "Well, that was the joke." Jed: "Mr. Brewster, you're an awfully nice feller, but I've heard a sight better jokes than that!"
The Clampetts went back to the hills for Christmas during the first season, but did not return there until the eighth season, during which several episodes were filmed on location in Kimberling City, Missouri. During this period, Shug Fisher and Elvia Allman joined the cast as Shorty and Elverna (Allman had appeared on an episode in the first season playing the same character).
One constant throughout the series was that the Hillbillies, who were scrupulously honest, were surrounded by cynical, conniving and money-hungry "city-folk", whose plans were always foiled (usually unknowingly) by the Clampetts.
Read more about this topic: The Beverly Hillbillies