Just before Yaakov Avinu passed away, he gathered his sons together, and addressed each one of them in accordance with their individual needs and character traits. There was one exception: Shimon and Levi who were addressed as one. The Torah recounts Yaakov's admonishment: "Shimon and Levi are brothers; their weaponry is a stolen trade. May my soul not enter their conspiracy, may my honor not join their congregation, for in their wrath they killed men and at their whim they uprooted an ox. Cursed is their wrath for it is intense and their anger for it is harsh, I will separate them within Yaakov and disperse them within Yisrael" (Bereishis 49, 5-7). Rashi notes that even when Yaakov admonished his sons, he did not curse them; rather, he cursed their anger.
Rav Wolbe (Shiurei Chumash) related that his rebbe, Rav Yeruchom Levovitz, was once asked if it is permissible to hate a Jew who does not observe the Torah and mitzvos. Rav Yeruchom answered that such behavior is forbidden for most people, because they cannot differentiate between the person and his negative middos. Hence, they will end up hating the person himself which is prohibited. He added that a great person can make this distinction whereby he would hate the person's actions, and, nevertheless, love the person himself. Rav Wolbe continues that Yaakov displayed this greatness when he cursed merely Shimon and Levi's anger and refrained from cursing Shimon and Levi themselves.
Rav Yeruchom would say, a person with negative middos can be compared to a closet full of diamonds and pearls that has a rotten apple in the middle. Would anybody even entertain a thought of disposing an entire closet worth millions merely because it also contains a moldy apple? So too, every person intrinsically is worth millions. Negative character traits are a rotten apple that must be dealt with, but should not diminish a person's worth which inherently is invaluable.
This is an idea that, if properly internalized, can drastically change our relationship with our fellow man and our assessment of ourselves. We will be able to look at the big picture and appreciate the diamonds in spouses, relatives, friends and colleagues, without allowing a rotten apple to cloud our perception. Likewise, when we stand back and assess our own spiritual well-being, we will begin to take notice of our many qualities and strengths. This will allow us to focus on polishing these diamonds and pearls without getting disheartened or even depressed due to a few rotten apples!