Warning! Spoilers ahead for Young Sheldon season 6 finale. Sheldon commits a big crime against Missy in the season 6 finale, but it shouldn't be surprising since it has already been explained more than four years ago. Because of his lack of social awareness, the boy genius is prone to making a lot of gaffes. Most of the time, however, he easily gets forgiven, with the people around him fully knowing of his flaws. That includes Missy, who has been mostly patient and gracious to him over the years. In the two-part season 6 finale, however, Sheldon appears to have finally crossed the line with Missy.

Interestingly, however, his latest mistake shouldn't have been expected.

After years of being the most understanding and responsible Cooper kid, Missy has become quite the problem child in season 6. She attempted to run away and drive to Florida with Paige by stealing George's truck. While she has already been reprimanded for her actions, it doesn't seem like she has learned her lesson. The arrival of Pastor Jeff's niece, Tonya, somehow exacerbated her rebellious tendencies. They have been able to get away with sneaking out at night — until Sheldon caught them and ratted them out in the .

2 Young Sheldon Season 2 Shows That Sheldon Can’t Keep A Secret

Sheldon's decision to tattle about his sister makes Missy understandably mad, especially since Mary and George have barely addressed her issues about always feeling ignored. For what it's worth, the boy genius' decision to tattle about her shenanigans is rooted in his concern for her. Missy tries convincing him to keep his mouth shut, and Sheldon tries really hard to keep his sister's shenanigans.

That being said, eventually divulging the truth shouldn't be unexpected from him, considering his inability to keep secrets as seen back in season 2.

In 2018's season 2, episode 4, "A Financial Secret and Fish Sauce," Sheldon was doing the Coopers' taxes when he discovered an unaccounted expense. Asking George about it, the family patriarch asked his son if he can just overlook the discrepancy. Sheldon tries really hard just to keep his dad out of trouble. Knowing that he wouldn't be able to lie to Mary's face, he went to great lengths to evade his mom. He even went on his first sleepover at Tam's just to get some separation.

In the end, he had to blurt it out. This properly demonstrated that Sheldon just doesn't have the capacity to lie long-term.

1 Big Bang Theory Supports Sheldon’s Inability To Keep Secrets

has always been criticized for its lax approach to continuity. That being said, this particular trait for Sheldon was also fully demonstrated in , particularly in season 2, episode 1, "The Bad Fish Paradigm," where Penny asked him to keep her insecurity about dating Leonard from his best friend. In season 3, episode 20, "The Spaghetti Catalyst," Sheldon once again proved that he just isn't cut for lying. He made a poor effort to sneak out of his apartment to meet Penny and have dinner with her on the heels of her break-up with Leonard.