Good and evil are very different things. Evil does what ever it wants to get what it wants without any regard to who get hurts. Good looks out for the betterment of the world. It wants to make things better. It has morals, respect, loyalty, and courage to make the world a better place. I once heard a really profound quote. It said evil does what ever it wants to (win) no matter how unscrupulous it is and that is ok because it is the nature of evil. But good can not lie or cheat. Good must do the right thing no mater what evil does to them, BECAUSE WHEN GOOD TAKES ON THE WAYS OF EVIL IT BECOMES EVIL AND EVIL WINS. You need to trust good to win on its own merits.
Just because someone did something mean or evil or hateful to you does not justify you doing the same to them. IF YOU ACT LIKE THE EVIL PERSON THAT HURT YOU, YOU HAVE JUST CROSSED OVER TO THE EVIL SIDE, and EVIL WINS. You have just given those you are mad at exactly what they wanted. You allowed them to drag you down to their level. You can not think you are better then someone else if you do the bad things to them they did to you. Just because you think you are on the side of righteousness does not give you the right to do the very thing you are angry at someone else for doing. Evil wins.
Then there is karma and trust me it exists. I have been smacked down by karma a few times. If you do bad things bad things come back to you. If you wish harm to someone else harm comes back to you. Karma is the great equalizer. Karma knows even if someone hurts you it does not give you the right to hurt them back. We all have to make our own choices. Do we want to be good people and put good into the world, or do we want to be influenced to do the wrong thing by people who make a career of doing the wrong thing? I know not what choices others take, but USUALLY I will take the high road most of the time. On the rare occasion I have allowed my darker side out, I have ended up regretting it.