Warning! Spoilers ahead for Young Sheldon season 6 episode 5.

George's (Lance Barber) insult against Sheldon (Iain Armitage) on Young Sheldon season 6 has long been proven by Penny (Kaley Cuoco) on The Big Bang Theory. Ever since George lost his full-time job, he has been spending time at home, which means that he has more interactions with the rest of his family. He's had a short but interesting back-and-forth with Missy (Raegan Revord), and now, it's Sheldon's time to have verbal sparring with his dad. George's zinger against his son isn't exactly new, however, since it was previously used on The Big Bang Theory.

In Young Sheldon season 6 episode 4, "Blonde Ambition and the Concept of Zero," George asks Sheldon to tutor Billy (Wyatt McClure), and to be able to convince him, he used reverse psychology on the boy genius by challenging his ability to teach. This isn't the first time that Sheldon's teaching skills was questioned. On The Big Bang Theory episode, "The Gorilla Experiment," Sheldon attempted to teach Penny Physics, so she could better understand Leonard's (Johnny Galecki) work. After several starts and stops, however, she was still struggling, causing her to declare that Sheldon sucks at teaching - and she wasn't wrong about it considering how badly he conducted himself throughout the whole session.

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Why Sheldon Can’t Be A Good Teacher?

howard and sheldon talk to women in science - the big bang theory

There is no doubt about Sheldon's intelligence - the problem with him is primarily his attitude. Since Sheldon inherited Mary Cooper’s personality in terms of both ego and a habit of being judgmental, he also has a difficult time leveling with people who aren't as smart as he is. Typically, his first instinct is to criticize and insult them, but because he is teaching them, he can't just do that. If anything, Sheldon was still mindful of his manners when he tried teaching Penny on The Big Bang Theory. Things were different when Howard (Simon Helberg) joined his temporary class. Since Sheldon already hates engineers and engineering like his astronaut friend, he didn't hold back in looking down on him. Little did he know that Howard was perfectly capable of attending his class; in fact, he was a great student, Sheldon was just a bad teacher.

Penny Has A Special Connection With George

Young Sheldon George makes dig at big bang theory penny

Previously, George has indirectly criticized Penny on Young Sheldon. This and having the same criticism against Sheldon aren’t their only connection, however. Given the prequel nature of Young Sheldon, featuring the cast of The Big Bang Theory on the spin-off is tricky and since the Cooper patriarch was already dead when the nerd-centric sitcom began, he never got the chance to meet the Pasadena gang. Despite that, Penny knows about George's impending cheating scandal, which is something that Young Sheldon is gearing up to tackle. Interestingly, she is the only one to that Sheldon opened up about the traumatic experience of catching his dad with a different woman. Since their heart-to-heart talk about the matter on The Big Bang Theory season 10, it was never brought up again in the series.

The Big Bang Theory featured a lot of smaller dynamics within the Pasadena gang. Sheldon's true soulmate may be Leonard, but his bond with Penny is also quite special. She was patient and loving, but she never coddled him. Somehow, it's reminiscent of his relationship with George on Young Sheldon. While Mary (Zoe Perry) tends to cater to the boy genius, his dad was appropriately stricter on him, connecting Penny and George by the fact that both of them have no issues calling Sheldon out.

Young Sheldon season 6 airs Thursdays on CBS.

Next: Young Sheldon’s Science Dilemma Was Solved By Howard In Big Bang Theory