Two questions, Eli.  Isn't revenge both natural but inherently evil in itself?  Secondly, do 2 wrongs make a right?

There was an interesting discussion on Nicky Campbell's 'Your Call' last week where this was the underlying topic.  Does a harbouring of feelings of revenge (also referred on the programme as a refusal to forgive - albeit not forget) actually do damage to the harbourer?  Is there not a danger that it acts as a canker inside slowly poisoning all aspects of one's life?

Andy, two wrongs don't make a right, no, but it's the only kind of "justice" that makes sense in certain circumstances, because we don't have such a system....that and it's the only kind of justice folk as evil as that understand!!!  And no, I don't think that revenge is, in itself evil!! I think it's natural!! And it's not against completely innocent people!!!!!!!
I also don't think feelings of revenge are the same as refusal to forgive....one is an active feeling, which for most of us could never happen (not least because in my situation I don't know identities of those involved......the guy who attacked me because he was a stranger and the girl who murdered my friend because she was afforded a new id on release......that and all the other help she needed(!!) and the other an inability to feel a certain way (ie forgive)
And yes, probably the only person to suffer in feelings of hatred is the one feeling the hate -  that does tend to be the way of it - but the logic of that does NOT make it a given that it's possible to say "ok then" and forgive - I still maintain that some things ARE just unforgiveable!!