There is a saying that goes " If you lie down with dogs you'll get up with fleas." No I don't think it is okay (however tempted we might be) to stoop to the level of the " bad people ."

I do think it is okay to get "justice." for the " bad people's " actions against us. For this we need to incorporate some authority above us to aide us in getting justice. Personally I like the justice angle as it's effects will stick much longer than anything I could do.

Society has that right, but not an individual.
Sometimes "good things" and "bad things" gets clouded by cultural or other influences.
I live in an area which believes that you should take as much advantage as possible in any given situation. Stealing here is blamed on the one who left something where it was obtainable and a temptation for the one who stole it. It isn't the fault of the thief - he was only taking advantage of a situation that provided him with an opportunity.
I have stopped calling some of these people "friends" - not because of how they have been with or done to me, but how they have treated others. Cheating, stealing, enslaving where possible, and other "wrong" behavior (by American standards) is a way of life for many in the world. Power corrupts, and absolute power corrupts absolutely.
It is possible to do something "bad", and even to appear to "get away with it" - but there will be a reckoning. A person has to "live with" their acts and deeds whether they believe in a Deity or not.

The terms "good" and "bad" are subjective & relative to the situation. Everyone has their own perceptions resulting from life experiences, their own beliefs & value systems. Some people get rabid when they hear the term 'situational ethics', but it's a fact of life when action has to be taken to prevent further harm.

There are few instances of absolute black & white, & precious few universal truths.

I'll associate myself with Sylk's comment.
I also agree with the quotation cited by ROLLINGCURLERS.
"My question is, is it okay for good people to do bad things to bad people?"
No. And for me, that includes the human creation, society.
As for "justice", it is also subjective. I do not believe Americans, in general,
have a clue what justice is.

I am an agnostic but I once read an excellent statement on sin: sin is when you deliberately and knowingly hurt another person. I truly believe there is wisdom in that statement. So for me, when someone calls somebody fat, as an example, that is very harmful. I am now going through a situation where someone has really hurt me....do I try and hurt back? No, I think it is wise to just let it be. It is so hard just to let it be but I am giving it my all. So, doing good or bad are not just about the big things in life, like murder...most often it is about the small things that add up....do we get even or do we just let it be..I guess it depends but the older I get, the more I tend to just let it be

Two wrongs don't make a right; and being bad to someone to get them back for being bad to you serves no productive purpose in your life, or theirs.

Define "bad", first. People have different value systems. Intentionally hurting another is 'bad'. Lying to another, to 'protect' them from the truth some consider 'bad,' too.

Beyond the obvious, stealing, assaulting, killing another human, the definition of 'bad' comes into play before one can honestly answer one would think.

"Bad" to me means doing something harmful to someone or something. The only time I can think that it is OK to do something I'd normally think of as bad would be if my life or someone else's was being threatened. It would almost have to be a self-defense situation for me to do it.

we often think that bad means something physical done to us or things like stealing from us....we do not pay any attention to how we use language....words can be very destructive and harmful....people have committed suicide over the careless use of words

Believe me, Pamela4, I know the power of words. I try my best not to use them in a harmful or hurtful way.