I have been blessed to learn from many wonderful rebbeim in my life, each of whom has left an indelible impression upon me.
One of those rebbeim was my 11th grade rebbe, Rabbi N. Aryeh Feuer. I loved his shiur. Aside from being engaging and challenging, Rabbi Feuer was somewhat unpredictable in shiur, saying funny or unexpected comments at any time. He once explained that he did that to keep our attention by keeping us on edge. I recently told Rabbi Feuer that I try to emulate that component of his teaching style with my own students.