The later-season changes in Drysdale and Miss Jane
In the earlier episodes, Drysdale is seen as a respected executive of the city. Sure, he's somewhat greedy - what bank owner isn't. But you also get the feeling that he really likes the Clampetts and is not entirely a bad guy.
Miss Jane is shown as a well-educated woman who speaks many languages, understands social graces, and could easily step in and handle most situations if Mr. Drysdale is unavailable.
Fast forward to later seasons where Drysdale is now a penny pincher, totally full of greed and selfishness, and treats his employees like they're working in a sweat factory. He even tries to cut off their benefits. Not to mention foreclosing on people's loans.
Meanwhile, Jane is now living in a one-room apartment barely able to make ends meet. She's forced to work weekends and is blamed when all of Drysdale's nasty schemes blow up in his face. Once a respected executive assistant, she is now a low-paid grunt employee.
While there are some funny scenes with these two, it's a shame that they were turned into such miserable cartoon characters.