The Greatest Principle of the Torah
Ben Azzai found the Torah's great principle in the verse that every person descends from Adam, made in the image of Hashem.
Rebbi Akiva taught that the mitzvah to love your fellow as yourself is a great principle of the Torah. Ben Azzai pointed to an even greater one, the verse in Bereishis: This is the book of the generations of Adam, on the day that Hashem created man, in the likeness of Hashem He made him. The Midrash gives an example: a person might think, since I was insulted, let my friend be insulted too. Rebbi Tanchuma answers that if you do so, know whom you are shaming, for in the likeness of Hashem He made him. Ben Azzai's verse does not depend on how we feel. Every human being, without exception, comes from the same Adam and carries the image of Hashem. The respect we owe each other rests on that foundation.
Source: Sifra, Kedoshim 4:12 (on Vayikra 19:18 and Bereishis 5:1); Midrash Bereishis Rabbah 24:7
The next time someone irritates you, in traffic, on the phone or at home, pause before you answer and say to yourself quietly: this person was made in the image of Hashem. Then let your words reflect that. Try it at least once a day this week. Over time, that one sentence can change the way you see everyone around you.