Awe for One's Teacher
Torah learning
Rav Yehuda Zev teaches that a ben Torah grows only when he holds his Torah teachers in awe, as Pirkei Avos (4:12) says that the awe of your teacher should be like the awe of Heaven. That is why, for all his warmth, he kept strict discipline in the yeshiva. He also told his students to use their yeshiva years for the greatest growth, especially in gathering Torah knowledge, since the more they learned then, the greater their influence would be later in life.
Source: Pirkei Avos 4:12; teachings of the Manchester Rosh Yeshiva, as told in Yated Neeman (D. Sofer)