I used to manage an apartment building when I was younger, so I know what you are saying. The problem is, people today have been brought up with no manners and no respect for others. Most of them come from one-parent homes. There is no religion in their lives. All they have is pornography and movie violence, violence in video games, violence in music. They are conditioned by television and Hollywood to react with physical violence to any affront or perceived insult. They are rewarded by society for acting like small, petulant children. When they get angry or frightened, and their reasoning ability cuts out, this media conditioning cuts in. I'm surprised there aren't a hundred times more incidents like this one.