Florence Pugh wrote and performed two songs in Una buena persona (2023), "The Best Part" and the piano track titled "I Hate Myself."
In a 2023 interview with HeyUGuys, Zach Braff spoke about the personal significance of model trains in his life and how it informed the film: "I had a model train set as a child. All of the writing I do I pull from life experiences and my model train set was my favorite thing. It was in the basement of my house, just like Morgan Freeman's is. And whenever life felt out-of-control I would retreat to this little train set. Mine wasn't nearly as fancy as Morgan's character, but I got so much pleasure and it was meditative. I didn't realize at the time, but for me as a child it was meditative and quieting. And so I added that for Morgan's character, who doesn't have a lot of control and has had a lot of mayhem in his life. And it's where he goes to retreat and be meditative and create his own world that he can control."
Director/Writer Zach Braff and lead actress Florence Pugh were in a relationship for three years. They broke up in early 2022.
In this film, Florence Pugh and Celeste O'Connor play characters who are 10 years apart in age, as it is stated in the dialogue that Allison is 26 and Ryan 16. In fact, there is only a little under three years' difference in Pugh's and O'Connor's actual ages --- Pugh was playing a character of roughly her own age while the 23-year-old O'Connor was playing a teenager.
The film will be dedicated to Harold Irwin Braff and Shoshanah Braff, and Nick Cordero.