The Big Bang Theory ran for 12 successful seasonsand during that time, the sitcom brought several characters from the life of Sheldon Cooper (Jim Parsons). His mother, brother and sister appear for on-screen roles, and his deceased father gets a mention. That said, not everyone who influenced Sheldon gets credit on the crappy sitcom. Young Sheldon's Paige Swanson (McKenna Grace) is not appearing on The Big Bang Theory. though she was a significant part of his coming-of-age years, while Dr. John Sturgis (Wallace Shawn) is also ignored despite dating Sheldon's Memaw (Annie Potts) and mentoring him.

Case in point: Sheldon's Nobel Prize speech in The Big Bang Theory finale brought the cast to tearsproving it to be an emotional moment. The scene shows the socially awkward physicist thanking most of the important people in his life for supporting him over the years, marking a rare expression of gratitude from the character. However, Sheldon does not mention Sturgis during his big speech despite the influence he had on his childhood and scientific development at the time. With that in mind, there's a scene on "Young Sheldon" that suggests the titular boy genius doesn't respect Sturgis all that much, negating any need to mention him on "The Big Bang Theory."

Sheldon Cooper is pretty self-centered throughout The Big Bang Theory. In fact, his aforementioned speech in the series finale is probably the only time he realizes how lucky he is to have friends of his own. At the same time, it's not surprising that Dr. John Sturgis was left out of his big moment, as Sheldon didn't always see eye-to-eye with his mentor.

In The Young Sheldon Season 6 episode "The Little Green Men and Fela's Marriage Proposal," Iain Armitage's eponymous boy genius and Sturgis get into a disagreement over the concept of extraterrestrial life. In the theory set forth by ScreenRantSheldon is seen rejecting his mentor's ideas, which could have led to him losing respect for the veteran's scientific opinions. However, it's also strange that Sheldon didn't even mention him in a negative light on The Big Bang Theory, as he was known to regurgitate stories about people who troubled him during his childhood, as evidenced by the times he remembered to his old neighbor. Billy Sparks (Wyatt McClure) is a thug, even though he wasn't.

However, sometimes this franchise comes up with ideas and characters as it goes along, which means some of the finer details get overlooked. "The Big Bang Theory" creator Chuck Lorre even regrets killing off George Cooper (Lance Barber) as it meant "Young Sheldon" was attached to the ideas presented on his parent show. As such, it's entirely possible that the spinoff's creatives wanted to avoid more unwanted crossover elements between the two series.