You’re enjoying their misery
You are enjoying watching this friend suffer. She made you suffer in some way, and now you think it’s only fair that she suffers. Perhaps you think it’s only right that she suffers as much as you did, so you will forgive her once you feel she has suffered as much as you did. You’re overlooking the fact that, to show mercy means to allow someone to escape their due punishment. It actually means not punishing somebody. But, you’re pretty focused on getting even in some way. And you get a little thrill when this person leaves you five voice messages, crying, all of which you don’t respond to. You feel like you’re winning something.