I think therefore, I am
You're so convinced you exist that you think the whole world is just a part of your thoughts. You're like the main character in a movie, and everyone else is just background noise.
I'm real, you're just in my head. That’s why I’m the main character.
You think I’m real? I think I’m real, and you’re just a side character.
I exist, and you’re just a part of my brain’s imagination.