Who is your lifetime teacher and why?

A Mr Neil Nagarkar recently posted a youtube link in a forum thread, citing a recording from a very profound British Philosopher, writer and speaker - Mr Alan Watts.

It was only some days ago I was also pondering the outcomes of our lives, the mentors along the way and the people who have tought us something wise that we have held with us until today. Our surroundings, our thoughts and our way of life is often guided by a subconcious that is telling us, guiding us and leading us down a path. These thoughts are a mixture of our life experience, people we love, people we have used as mentors or teachers and a splendid arrangement of human interactions along the way.

So, if you had to choose one and only one person who has had a life impact on you (whether popular or unknown), let us share that person with the world.

I would love to hear who's yours is and If you're lucky, I may just share mine :)