During this past spring semester, a student of mine asked me how I knew I wanted to teach. I hadn't thought about it. I have always had the desire to share what I know with people and encourage them.
As a teacher, I don't say things I don't mean. I will not say something was good when I don't feel it was. However, it is a rare experience to not find something positive about a student or their work. If someone simply doesn't care, I do write them off. There is a fundamental joy I get when I work with students sharing knowledge and watching them develop.
I encourage total strangers too. What gets me out of bed each day is the drive to do new things, master certain skills and explore. It is very difficult for me to understand people who do not have any interest in stepping outside of themselves or their comfort zone. I'm heading towards 50 now and I hope I can live another 50 years in order to do all that I would like to do or try doing.
Perhaps it is judgmental of me to push others hard whether I am a student, friend or collaborator. I say things like "You are too hard on yourself" or "you do have talent: you need to work at more is all" not to ingratiate myself to that person (I have encouraged people I don't even like)but because I believe so strongly in potential. As a teacher and a continuing education student I have seen middle-aged people return to school or go to college for the first time to get a B.A. degree. One of them said to me "You know, in four years I'll be 54 when I graduate" and I said, "You'll be 54 anyway so you might as well have made strides in some way." Nowadays people retire much later especially if they enjoy working or particularly enjoy what they are doing for a living. The notion of finding new and better ways to do things is seen as a positive rather than something to fear.
Encouragement is something we all need. We can't rely on it as fuel with which to move forward and pursue our goals; we have to find ways to encourage ourselves when there is literally no support around. Nobody wanted me to pursue the arts in my family because of the unpredictability of the field(s) and difficulty in obtaining steady work. But I went for it anyway. I know it can feel very isolating when no one else seems to care about your goals and aspirations which is why I encourage friends and strangers to go for it - what makes them happy, what experiment they might want to try, what new direction they want to pursue in life.
So how do you know that you want to be a teacher? Or, how do you know you want to be a writer? An actor?
You just know. And you dig down deep inside you to find the courage and the strength to go for it. As you travel, you encourage others in their endeavors.
I don't see any other way to be.