Except for retaliating the hurt cause by others, there are more reasons and purposes to do so.
Sometimes people killing to give vent to his anger. They give vent their anger to some others rather than the one really made them angry. Maybe because they do not have the ability to hurt the principals or they can not bear to harm that one. This kind of killers are always upset and nervous so we should recognize them as early as possible. To stop and help them before they do any thing silly and dangerous.
There are also another group of people, they killing because they are afraid of someone or something. They can not bear others’ threatens and become terribly afraid to those ones who bully them. In order to make themselves feel safe, they will choose to get rid of that person by killing him. So do not bully others or one day you will be “bullying”.
The last one is the most different and special one. Those people, they killing others to prove themselves are strong and even to have fun in those killing processes. They are kind of psychopaths or we sometimes call them genius.
Most of time, they have a completely different world with us. We can not understand each other at all which is really hard to keep yourself calm or peace. They just find an provocative thing to work on and go across the line of law is apparent a “nice” choice to them.
People killing people no matter why is also for their own benefit which is selfish. However I do not think this is totally wrong. Humans are living things, they can not stop thinking at all and of course people thinking about themselves at first. No one will care of you if you do not care about yourself. Humans are hard to explain but that is also why they are so interesting:]
--- By Linda