What is at the root of meanness?

Answer 1

Usually it's because people have such poor self image that they seek ways to make themselves feel better by minimizing others. The underlying attitude seems to be, "If I can dominate someone, it makes me better."

Of course, civilized, intelligent people don't need to feel that way, and naturally, we know that to improve ourselves simply requires that we seek education or in some other way work on our attitudes and general knowledge.