I was an adjunct for a few years and I fit into neither of your "categories". When I taught my first class, I did it as a personal favor to the department chai

I was an adjunct for a few years and I fit into neither of your "categories". When I taught my first class, I did it as a personal favor to the department chair, whom I had a good relationship with (I'd often come in to different classes and speak to the students about our field and such). A few days before classes began, the instructor for this particular course "fell through" and she asked me if I would be willing to teach the course. After some thought, I gave in and agreed. I ended up teaching several different courses of a few years and I didn't do it for either of the reasons you mentioned. While teaching the first course, I found that I genuinely enjoyed it. At the end of that term, I received my (anonymous) evaluations from my students and they were outstanding. I was compared to (and rated much better) than their previous instructors, many of whom I considered friends. I agreed to keep teaching. I certainly didn't do it for money. I was only paid for the hours I spent in the classroom -- no pay for "prep time", the hours I spent grading papers, etc. All things considered, I earned less than $10 per hour. I could have made more working at a fast-food restaurant -- and probably been less stressed out. I taught because I truly enjoyed it and became, to use your word, quite "passionate" about it. To this day, I remain friends with a lot of my former students -- many of whom now work in my field. I've even had the pleasure of working with a few of them professionally. It feels good to see them "grow up" and to have them thank me, years later, for making a difference in their education. Sometimes I actually miss it but, then again, I never did it "just as supplemental income".