The Flight Attendant proves how unfair and offensive Sheldon's treatment of Penny was in The Big Bang Theory. In 2019, the CBS long-running sitcom wrapped up its run after 12 seasons. This came as a shock considering that the network just announced that it was contemplating ordering at least another year of the show. Since its end, however, a lot of its main cast has moved on to do new projects, including Kaley Cuoco, who successfully transitioned to playing Cassandra Bowden in The Flight Attendant which she also produces for HBO Max.
As someone who was in The Big Bang Theory throughout its full run, leaving her character Penny and playing a different one in Cass was doubtless not an easy process for Cuoco. Despite that, The Flight Attendant was an instant hit, and she was praised for her performance as the titular character in the show; the role earned her Critics Choice, SAG, and Golden Globe nominations. But as it turns out, other than bidding goodbye to her old sitcom character wasn't the only hurdle that the actress faced while filming the dark comedy. According to her co-star Michiel Huisman who played Alex, Cass's brief lover, Cuoco didn't know how to shoot a love scene.
In The Big Bang Theory, particularly in its earliest seasons, Penny was depicted as someone who would sleep would anyone. She would be regularly castigated for her sexual activities, and no one criticized and humiliated her more than Sheldon. But in reality, Penny didn't deserve to be treated like that, mainly because she was a grown woman who could do what she wanted. The worst part of this is that Sheldon also actually painted an inaccurate picture of her; throughout the series, she was never really shown sleeping with random guys. In fact, she was only ever really shown sleeping with Leonard, whom she eventually married. Hence why when it was time for the actress to do a similar, albeit more intense, intimate bit with Huisman on The Flight Attendant, she struggled.
While Penny did like to go out with men - and she didn't deny that some of those dates ended up back in her bedroom - there was no reason Sheldon should've ever repeatedly made her feel bad for having those casual relationships. Looking back, The Big Bang Theory used those misogynistic comments to get some cheap laughs from the audience. In fact, this was mainly the role Penny played in the sitcom for its first few seasons, although eventually, as the seasons went by, there's a noticeable change in the depiction of the character. It's unclear if this change was motivated by criticisms about the sitcom's deeply problematic handling of the character, and/or if Cuoco herself spoke up about wanting it to stop. In any case, it's a step in the right direction, and was better later than never.
This is doubly true when taken into account the specific dynamic Penny tried to cultivate with Sheldon. Though nobody deserves to be shamed for their romantic endeavors, from The Big Bang Theory get-go, Penny had been nothing but patient with Sheldon, trying to be accommodating to all of his quirks - only to receive callous remarks as a reward. The Pasadena gang's excuse for tolerating his bad behavior was because he supposedly didn't mean to be offensive, but that didn't excuse his misogynistic behavior, especially to someone who'd been nothing but a reliable friend to him.