1. First, You creators Greg Berlanti and Sera Gamble originally pitched the series in 2015 — it was supposed to air on Showtime.
2. The series is actually based on two novels by Caroline Kepnes titled You and Hidden Bodies.
3. In fact, Stephen King praised Kepnes's novels, saying, "Totally original. Never read anything quite like it…Hypnotic and scary."
4. While there are a few differences between the book and TV series, one of the major ones is Paco doesn't exist in the books.
5. Five of the 10 episodes in Season 1 were directed by women.
6. Penn Badgley knew from the start Joe and Dan Humphrey from Gossip Girl would be compared to each other — he even said that Joe ends up being a progression of who Dan could've become.
7. When Elizabeth Lail first auditioned she didn't know what was going to happen to Beck — she read the book only after she got the callback.
8. Dr. Nicky's technique of writing cards and drawing was actually based off something John Stamos's real-life therapist does.
9. Elizabeth and Penn had to attend an eight-hour safety course before they were allowed to film on the NYC subway tracks.
10. One of the scenes that creeped Shay Mitchell out the most was when Peach spied on Beck in the bathtub.
11. Due to the fact that most of Joe's lines are actually voiceover, Penn said that most days he wouldn't have much dialogue to actually memorize.
12. In fact, Penn's first acting jobs were doing voiceovers for a radio station and Nintendo 64 video games when he was only 10 years old.
13. Creator Sera Gamble said that one of the reasons she thinks people are rooting for Joe and Beck, despite it being creepy, is that audiences are wired to root for the love story.
14. The cast all agreed that filming during the #MeToo movement definitely affected filming more and more — especially when it came to filming scenes between Beck and Joe.
15. While filming, Penn often wondered if he was making Joe too likable.
16. John said one of the hardest parts of playing Dr. Nicky was not falling into his old comedy ways — he tried to be as serious as possible.
17. On set, Shay would often joke with Penn about his lack of social media knowledge.
18. Unlike with some of his other projects, Penn actually watched some episodes of You just to see how Joe was coming across on screen.
19. Finally, just like the second book, You will take place in Los Angeles during Season 2 instead of NYC.
