Chazal say: הַקּוֹנֶּה עֶּבֶּד עִבְרִ י כְקוֹנֶּה אָּדוֹן לְעַצְמוֹ (Kiddushin 20a)—one who purchases an Eved Ivri (Jewish slave) is as if he has acquired a master for himself. If you only have one air-conditioner in the house, the Eved gets it, not you (Tosafos). This is a hint to all relationships where you have 'nebachs' under you. The worst sin is looking down at others (unless you have deep inferiority issues; then you may have a Chiyuv to look down at others).
Looking down is Ga'ava; what Paroh and Hitler Y'mach Sh'mo were guilty of. So how do we work on not looking down at a Shafel (lowly) type of Yid who has a hole in his ear for not listening at Har Sinai, and making a mere human his master? By working on your Middos, and by Davka considering him even bigger than you.
