Usually when we dislike someone we may not necessarily "hate" them per se, but we'll tend towards aversion, detachment, or indifference. In other words, our hearts grow cold towards others (especially those we dislike) through these three forms of hatred.
Also, have you ever considered complaining about and "bad-mouthing" others? We all like to let others know when we've been offended by complaining about and "bad-mouthing" others. Does a homeless beggar ask other homeless beggars for alms? No, because all he'll get is meaningless sympathy. This is what the world gives us when we complain about and "bad-mouth" others: nothing but meaningless sympathy.
If you want to live a life of love, then we need to avoid not only hatred but aversion, detachment, and indifference. And if someone offends us, don't complain about or "bad-mouth" them to others. Instead bring your complaints to God who gives true and lasting comfort to us and teaches how to behave with love and wisdom in difficult and sorrowful circumstances.
