I caught notice of this month's accretionary wedge (hosted at Metageologist) just in time.
So the question is, who was my most important teacher?
I went to a SLAC that had a 5-professor geology department. I wouldn't be able to suss out which professor was the most important - although I got a terrific base of geological knowledge, none of the courses were terribly earth-shattering, in terms of changing the direction of my career.
You know who made a huge difference in my geology career (and eventually, my life)? My college chemistry teacher. I'm paranoid about my pseudonymity, so I won't reveal her name here. Why chemistry?
I had always been a good student, until high school chemistry. Chemistry consisted of nothing but memorization and equations that didn't seem to relate to anything. After high school chemistry, I had pretty much ruled out "hard" science. Maybe I would understand something with fewer equations. (this train of thought is sort of funny considering that now I do lots of hydrogeology... helloo equations!)
I took chemistry in college because I needed two supporting sciences. But in this case, the professor was the opposite of my teacher from high school. She showed how all the pieces of chemistry actually fit together, and how the more you learned, the more everything made sense.
The chemistry I learned in that first course provided me with the base that helped me understand the underpinnings of geology - the stability of minerals, the conditions under which rocks were formed, and (most relevant to my career) the interactions between contaminants and subsurface materials.
I came out of that chemistry course with a terrific base of knowledge, and I had regained my academic equilibrium: I could ace a fast-paced, equation-heavy course. From then on, I continued to stretch myself to do well in difficult science and math classes. My chemistry professor changed my entire college career and was probably the catalyst for me to go on to (and be successful in) grad school.