Theorisbat
The existentialist fear that communication is nothing but coincidence. The disconnect between a speaker and the listener caused by the human condition of individuality.
As a child I was overwhelmed by Theorisbat: I suddenly became paranoid that no-one actually understood anything I said and likewise, I didn't actually understand anything they said but had invented their language in my head, and they were humoring me by letting me participate like a normal person in society.