Dreams.

I had a dream about an algebra lesson. The teacher who taught algebra to my class calls my former classmate to the board (I hadn't seen him in four years and didn't remember him; it was just a dream). On the board is the equation: 25x = 10 * 15. It's child's play, nothing special, but suddenly this guy writes that x = 25, and in parentheses, that 25*25 = 1303, and the whole class agrees with him, even the teacher. I, without saying anything, realize that something is wrong and wake up. I couldn't fall back asleep; it was 6:30 AM.