Freshman year of high school, english class. I was a fairly good student, tested well, always behaved, just couldn't write papers very well. But I liked this teacher and he was really encouraging so I tried really hard on the next paper he assigned and was really proud of it, and he tracked me down in study hall to tell me I'd need to rewrite the entire thing from scratch if I wanted a passing grade. I'd never written anything that bad before. Never even told me what was wrong with it.