The final season of The X-Files may not have been the best, but it had a couple really good episodes. The best may have been one centered around the Mandela Effect.
What is the Mandela Effect? The YouTube channel Not Exactly Normal explains.
In short, the Mandela Effect is how the brain makes people remember things incorrectly. As much as we may think of our memories as being fantastically accurate tools, the opposite is generally true instead. How bad can it get? See below.