Humans!
What differentiates one human from another is not their race, or the color of their skin. It is simply their ability to be aware of, understand, and then take responsibility for, the consequences of their actions.
This differentiation tends to segregate the species into those who see themselves as victims and those who see themselves as the masters of their world. Whenever these two views of life meet there tends to be strife and discomfort often resulting in high levels of frustration.