Seeing The Good in Every Man:
An important part of loving one's friends is seeing their positive aspects, rather than their deficiencies. When one does this, he is able to form a close bond. But if one pays attention to his friend's negative qualities, he won't be able to connect with him.
This idea is found in Sefer Me'ohr V'Shemesh (Parshas Vayelech), who writes: "The main shoresh of avodah is to love every Jew, both old and young, and even people who have turned away from the good path should be loved for the good qualities found in them...and then the impure forces will be unable to harm us and fear of Hashem will be increased as a result."