As a teenager 20+ years ago, I remember sitting in the basement of my parents' house one afternoon with my younger sister. She and I were having a conversation about nothing in particular, when I suddenly realized that I've had that exact same conversation with her before. I paused for a few seconds, then thought back to my recollection of the particular conversation in the past. I then remembered what I was supposed to say (in my memory), said it, and lo and behold, she then said the EXACT thing she was supposed to say. I then said my next "line," and she said hers. It was as if she and I were reading from a script. We exchanged two or three more lines back and forth, when I suddenly thought I would try and experiment! I then purposefully said something OTHER than the statement I was supposed to say. Her reaction? Here's where it got a little spooky. She looked at me as if I had not said a word... As if she were still waiting for me to say my next line.
I suppose this experience might be classified as deja vu, though it felt a little different than that to me while it was happening. It was eerie though how my sister would say EXACTLY what she was supposed to (even "is not" instead of "isn't" or other detailed phrases), every time she spoke. Has anyone else ever had any similar experiences?