In 2008, Joseph had already started to plan the story of "Don Juan", using the interval between filming to make notes in the notebook. This idea has been brewing in his mind for several years, and he has conceived different versions and different types of films in his mind. When cooperating with Seth Rogen in "The Anti-Cancer Me", Seth's enthusiasm for comedy infects Joseph, and it also gave him the idea of making the story into a comedy, such as a "somewhat misnomer Don Juan" . The first thing he thought of was that kind of masculinistic fitness freak from the east and west coasts.
Ryan Johnson, the director of "Loop Messenger", gave Joseph a lot of feedback when he was creating the script, and discussed with him repeatedly when editing. Another director, Christopher Nolan, who had collaborated with Joseph, warned him not to direct and act by himself, because this is too distracting and will increase the difficulty of directing. Joseph did encounter difficulties while writing the script. Because there is no experience, the most difficult thing is to write the structure of the whole story. On the contrary, the scene dialogue is the easiest, because he has to read and memorize hundreds of pages of lines since he was a child. He knows very well which paragraph is good and which paragraph needs to be deleted and repeated.
