I had this exercise at some point while at high school and in the psychology class. Everyone had to hang a blank paper on their backs. Then the professor asked

I had this exercise at some point while at high school and in the psychology class. Everyone had to hang a blank paper on their backs. Then the professor asked to start chasing the other peers and write in their papers what you thought about him/her in the most honest way. Since the paper was on the back it was very difficult to see who was writing what. At the end of the exercise I was in shock. I could not believe what the people around was thinking about me. The stuff they wrote was not in line to what I was thinking of myself. It was very hard. After about 25 years I am still recalling that episode. Interesting exercise nonetheless.