On retrospect, this should probably have been the first post. Anyway, the question here is relevant to any teacher at any point in time: Why teach?
Why go through the pain of preparing sessions, the agony of putting up with disinterested learners, the repetition of grading assignments or the frustration of messing around with technological glitches and faulty equipment?
For me, it is the satisfaction of witnessing a learner learn.
It really is as simple as that.