Good & Evil

Good and evil. Two sides of a coin. It often fascinates me how a person can describe what is good and evil. I watched this show called Dexter, basically a serial killer who kills other serial killers. But how come that's good in the viewers' eyes? Of course he is clearing the world and possibly saving future victims, but at the same time he is killing people. Other than serial killers, “bad” itself can be subjective to a human's experience. Example, in villages till this date a girl child usually gets married to an older boy. They have no concept of pedophilia, so it's good for them, but for those who have those concepts, it's bad. You understand what I am saying. And doesn't it seem that if there is something good, there is always going to be something bad about it as well? Like nuclear technology can produce electricity and can also bomb a country. Now what is good and what is bad in it? People will say it depends on who uses it and how. Then how can they decide what will be good…