That was quite a responsible work.
It's human to fail sometimes and become frustrated or angry and even clueless to a situation. We must accept that things sometimes just go not well. But I guess for the most part you were a good teacher and when you were in the same way attentive you are now, your students sure were fine with you. I most respect this work where one is responsible for so many souls. It should be honored more. I've heard in Japan teachers have a much higher respectable onlook than in western nations.