Given the social onus under which those who teach in the United States operate, particularly those who teach in the "useless" fields of the humanities, the question might well be asked as to why any of us do it. One answer to it, of which I was recently reminded, is that teaching allows us to re-experience the initial rush of engagement with what is being taught; we get to see things anew again, and with each new viewing, more of what we love is revealed to us. Being reminded of that love and being able to deepen it do much to make teaching worthwhile.
My literature class offered me such an experience last week. While I was lecturing on some piece of Middle English literature or other, I did as I often do and stopped to ask for questions. One came quickly, and the class turned to discuss it. (I was glad of it; student learning works better when students drive it.) As it happens, the question centered on a single line of text, one that had escaped my notice as I had read leading up to the lecture. (I am certain I saw it before, but not this time.) I commended the student on catching the note, albeit with a bit of a sheepish aspect to me (the repeated lesson of humility...), and class moved on with all of us having a better understanding of the text being read. That, I certainly appreciate.
Admittedly, it is not a flawless method. For one, new realizations necessarily mean that the old are insufficient--and they can be exposed...interestingly, as I note above. For another, students are not always so willing to go along with things or to run ahead. Sometimes, they are instead stubbornly opposed to opening up to new ideas and understandings, or they have by abusive educational policies at lower levels come to expect that "teaching" follows Friere's banking model, with the instructor depositing knowledge into them so that they may withdraw it at the appropriate time (and the accounts are not interest-bearing). I caution them against the desire to have me take such an info-dump on them, for I know it will be flushed away (and the metaphor of student and toilet that model promotes is not lost on all of them).
That the method has problems is not a reason to discard it, however. I have been told that much the same thing is true of parenting (although I have some weeks left before I get to experience it myself); the new child allows the parents to experience the world anew and to see the development of understanding take place, although at the cost of sleepless nights and splatters of various excrescences. Nor is the child always willing to open up to new ideas and understandings (problems of feeding come to mind, as does my own not-infrequently-belligerent resistance to experiences my parents offered me--for which I expect kharmic retribution in the not-too-distant future). Yet parenting is often viewed as a good and worthy thing; perhaps the issue is one of scale, since I do not place my teaching work on a level with my upcoming parenting work. But maybe it has given me a bit of practice I can use therein.