She made a mistake, let her know personally. I don't know, so I can't really say that if you were to go through with your plan that you would regret it later in life, but I know that I would. People do stupid things in life, that goes for everyone. What she did was wrong, but doing something equally as wrong in order to get back at her will only cause more problems in the longrun, and not just for her.
Sometimes no matter how hurt we are, or how much anger we feel toward another individual, we just have to let it go. Anger is a negative emotion, so acting on this negative emotion will have a negative result, no matter what angle you approach this from.
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"I can hammer a nail into a piece of wood, but that doesn't make me a carpenter."
"I'm praying for mayhem, I'm praying for tidal waves, I wanna see the ground give way, I wanna watch it all go down..."