Who taught me to ski?
1) Hockey Coach
2) Regular instructor
3) Freestyle Coach
4) PSIA guys at the ski school I worked for.
5) Own bad self.
I'd like to say, "taught my own bad self" because I spent a lot of time hacking around in back country as a child. However, the real progress started to happen when I joined a hockey team. So, the hockey coach that taught me how to skate actually also taught me my basic skiing technique. A few years later I parlayed that in to a week in intermediate lessons, then skied many many days/years getting better on my own. I don't really feel I took much away from those 4-5 lessons other than better, easier ways to tackle moguls at the most basic level.
Enter joining the Freestyle Team. There was where I transitioned to a truly advanced skier. Freestyle Coach had the biggest impact on my skiing for sure. Finally, I began working for the ski school and got a lot of good stuff from the weekly instructor clinics, along with just hanging with a lot of solid technical skiers.