Love and hatred are two basic emotions in human being, for which most of emotional states are mixture of these two feelings in varying ratios. Extreme love and hatred are rare as the prior one happens when somebody can die for somebody else while the latter one happens when someone can kill somebody else. For myself, I can only die for my family yet and have only handful of persons I can kill if the chance is ripe.
In mundane life, the forms of love and hatred exist in more practical shapes. People love when it is good for them while hate when it is bad for them. Even with the highest mastery of human relationship orchestration, it is impossible to stick to only one side. We all destine to suffer from effort to be loved and courage to be hated. Hence, things become more or less business in daily lives, which is tiresome at best. But, this is for human.
Here, as I get older and more experienced, I find reasons why many people love animals such as dogs, cats, rabbits, hamsters, parrots, and so on. Not a surprise, love and hatred from animals present in much more basic way than between human beings. There is not much reasoning, and sometimes it is unconditional. Some people love dogs or cats, which are popular choices, while some people have minority tastes (like me who is dying for rabbits). Saying rabbits, I truly love them partly due to their cute appearance, and mostly due to their inability of complex reasoning (or I would say "pure" in a nice way). Dealing with people gives a lot of stresses as their background desire, wishes, intentions, situations, even thoughts can be easily readable from all different kinds of ways. When I can see shallowly disguised mismatch between inner part (desire, wishes, intentions, thoughts et al) and outer part (verbal and written expressions, gestures, facial expressions et al), it disgusts me from the deepest heart. Rabbits (and maybe many low-intelligence animals) never give such feeling, as they are intrinsically incapable of doing so.
Life is puzzling, but this is particularly mysterious nature of it. Love comes from incapability while hatred comes from capability. But it also gives lesson. When we need genuinely trustful relationship, it shouldn't be based on business criteria. At least for love and hatred, things become healthier when we get closer to that of animals.