Reacting to negative justice in modern media.

Justice is seen as being held together by the courts, by law, and the law enforcement officers that go by the rules. In recent years there have been many TV shows that deal with a typical anti-hero. The most prominent ones that come to mind are characters such as Dexter Morgan, Jack Bauer, and Vic Mackey in Dexter, 24, and The Shield respectively. I'm choosing TV as an example but you can even see it in books such as "The Count of Monte Cristo". Each has a sort of vigilante justice that act when others are bound due to laws or a basic majority on morality and justice.

Do they act because the system is unjust, or do they act for their own selfish reasons? Each has a sense of right and wrong but no one can define what right or wrong is. Most modern law comes from common law where the majority of people speak up for the justice in society. Is it more dangerous with these shows to show that when the law falls short that it is ok to act if an injustice goes unanswered? Is revenge a dish best serve cold, or as a society have we accepted that there are people that will act when everyone else has their hands tied because of the law or even a majority opinion of what justice is?

Another question to ask is that when you see people in authority that are supposed to bring about justice act with injustice, does that blur the line in what the public can trust as justice?