Revealing mistake: When they leave their home to go to Beverly Hills and Granny is tied to her rocking chair on the top of the car, right before she hits the tree and comes off the car, you can see she isn't a real person. It's a dummy. (00:09:06)
Revealing mistake: When Ms. Hathaway is sitting in her office explaining to Jethrow her computer program for finding his uncle Jed Clampet a wife, she begins typing, but In the shots of the computer screen you can see she isn't typing anything.
Answer: He was being sarcastic. A beat up, broken down old truck driving through Beverly Hills. The guy considered it an insult.