Which personal theory about a TV show did you initially believe that was later confirmed as accurate?

One personal theory I had that was later confirmed true was about the TV show “Stranger Things.” Early on in the series, I suspected that the Upside Down was not merely a parallel universe but had connections with the Hawkins Lab’s experiments, possibly involving human subjects. This theory arose from the clues presented throughout the series, such as the seemingly intentional nature of the portals, the lab’s experiments on Eleven, and Dr. Brenner’s cryptic comments. As the series progressed, especially by season two, it became evident that those experiments directly contributed to the rift between our world and the Upside Down, confirming my suspicion. The narrative eventually tied the lab’s human experimentation to the dimensional breaches, which supported the idea that the supernatural occurrences had scientific origins linked to government activities.