Theo gives a whole seemingly heartwarming speech about how it doesn't matter if he doesn't succeed in school because Cliff should support him anyway because he's his son. Cliff responds: "Theo, that's the DUMBEST thing I've ever heard in my life. It's no wonder you get Ds in everything!"
- What makes it even funnier? The audience had just finished applauding Theo's speech.
- To put it in context, sit-coms in the 70's were absolutely rife with the "you should accept me no matter what I do" speech because of the whole generation gap thing going on at the time. And in every other sit-com, the scene ended with the older person giving in gracefully and a great big hug and hearfelt music and so forth. The audience reaction was absolutely typical for the time and everybody watching the episode was waiting for the hug. So when Cliff answers the way he does, it was unexpected and hilarious—listen closely and you'll realized that the laughter was very shocked laughter. This troper saw the episode with family when it first aired and we all just looked at each other like "what just happened?"
- Bill Cosby mentioned that he was worried about whether the show would succeed or fail based on that one moment. But once the pattern was broken and the audience reacted positively, he knew that the show would be a success from that moment on.
- During the Monopoly money bit, Cliff gives Theo a hypothetical $1200 a month for his "regular people" job, then immediately takes $350 for taxes.
Cliff: Yeah, because, see, the government comes for the "regular people" first.
(audience laughs and applaud THAT too!)
- Then afterward, Theo thinks he's free with $200 in extra money, living as a bus driver in Jersey with a motorbike while looking good. When Theo says, "No problem!", Cliff counters, "There IS a problem! You haven't EATEN yet!"
- The capper when Theo thinks he still has $200 a month left over:
Cliff: You plan to have a girlfriend?
Theo: For sure!
(Cliff wordlessly takes the rest of the money)
Cliff: (pointing to Theo's empty hand) "Regular people."