When my kid was very little, she asked me about a photo of me at the 2000 New Year’s party, and I replied, “Oh, this was before you were born.”
She didn’t like that at all. The idea that there was a time before she existed was intolerable. “I was born, Mommy! I was born!” she insisted. “I remember it! It was a great party!”
Gradually, she learned to understand the concept of the past. Instead of threatening, it became interesting, an object of curiosity.
This is what normal development of a human brain looks like. At first, the idea that the world existed before you and people have relationships and interests that are not about you is terrifying. But then you grow and get over it. Once you are completely over it, childhood ends.
Or if you didn’t go through the age-appropriate stages of development, it doesn’t end. Then, you run around, possessed by rage and destroying everything that reminds you that you are not the center of the world, that there are people who are valued more than you because of the important, grown-up things they accomplished, and that life existed before you and will go on after you.
This is the same thing that motivates the fantasies of “the world ending in 12 years.” It’s called “a narcissistic wound” and it makes people lash out in irrational, childlike rage against the intolerable knowledge that the entirety of human civilization is not about them.