True story: When I was in third grade, my teacher passed out small paper bags and asked us to decorate them for Valentine's Day. All the bags were to be attached to the bulletin board so we could bring Valentine's cards for our classmates and put each card in the proper bag. I drew a cartoon of a man holding a giant heart -- a very realistic-looking human heart. The teacher said my drawing was "gruesome" and she wouldn't let me use the bag. She handed me a new bag and said, "Here, use this."
Discouraging my creativity! I was traumatized for life!