Because we have evolved to live in groups, we have developed decent capacity for empathy, moreso than most other species. In fact the fact that we are so despondent about the evil in the world is a sign of the fact that we have the capacity for so much good.
The main caveat is that it is extremely easy to turn off empathy for sentient beings who are outside of the group or a threat to it. Most evil can be traced to this.
But we are generally pretty nice to others in our little social groups, so long as they do not threaten us or the group.
I think other primates are actually more aggressive than we are.
I don't know how well they work, but there are canine pheromones you can give your dog to see if that makes him more likeable. Like I always say; if you can't beat em, manipulate them.
http://www.entirelypets.com/dsp60dogapph.html