Do you agree that there is darkness within all of us? Explain

When I hear the word darkness, my mind quickly thinks that that means something evil is taken place. To answer the question, I do think that there is darkness within all of us. Why? We'll simply because there's a side of every one that has to be evil or mean. To be honest, I have a mean side and some of the kids I see today at school also has a darkness within them.