It's Always Sunny in Philadelphia star, Kaitlin Olson, says the main cast of characters will never "grow and be better people." The FX series is currently airing its season 15, making it the longest-running live-action comedy series in American TV history. It's Always Sunny follows a group of narcissistic friends who own an Irish bar, called Paddy's Pub, in South Philadelphia. "The Gang," as they are known, consists of Dennis Reynolds (Glenn Howerton), Deandra "(Sweet) Dee" Reynolds (Olson), Charlie Kelly (Charlie Day), Ronald "Mac" McDonald (Rob McElhenney), and Frank Reynolds (Danny DeVito).

Throughout the 15 season run, the It's Always Sunny crew have engaged in numerous shocking, disturbing, and humiliating activities. Some situations have seen the gang pretend to be mentally challenged in order to qualify for welfare, attempt to engage in cannibalism, and impersonate police officers to get free items from stores. While the group has received their fair share of humiliation and physical and emotional pain, they never really seem to learn from their mistakes. In fact, they've even recreated some of their past mistakes in future It's Always Sunny episodes, such as making another sequel to the 1987 buddy cop film, Lethal Weapon. It appears that the gang's inability to grow up is actually by design.

Related: It’s Always Sunny: How Lethal Weapon 7 Criticizes Hollywood Hypocrisy

Olson caught up with E! News to talk about It's Always Sunny in Philadelphia season 15, during which the actress mentions the main cast will never "grow up and be better people." Olson further elaborates that the creators and fans "want them to sort of never learn their lesson." Because the characters never evolve as people, Olson believes it's "one of the things that's funniest" to her about the show. View Olson's full quote about the It's Always Sunny gang's inability to grow as people below:

"We want them to sort of never learn their lesson and grow and be better people. It's kind of one of the things that's funniest to me about my character in particular because why would this person continue to try and impress these guys and be friends with them and want their approval after all this time? She's just trying to prove herself to them and has been for 15 years. That's completely ridiculous."

Mac, Dennis and Deandre at their bar

Despite their immaturity, It's Always Sunny in Philadelphia season 15 features an episode that sheds more light on the character's origins, which takes viewers back to the day Mac, Charlie, and Dennis bought Paddy's Pub. The flashback features a glimpse of Olson's character when she was actually known as "Sweet" Dee. During the episode, Dee has her own group of friends who are genuinely nice and caring people. However, during a roller-skating routine, Dee hits her head and instantly becomes the foul-mouthed character fans known and love.

The flashback in the latest season of the series is a good reminder of what the show really is. While many shows take overall bad or misguided people and turn them into decent members of society, It's Always Sunny in Philadelphia does the opposite. The episode shows Dee was originally a nice person, but is then turned into the narcissistic monster who never learns, much like the rest of the gang.

Next: It's Always Sunny Season 15 Perfectly Mocks Its Own Censorship

Source: E! News