Usually, it is not just feeling anger about someone but protecting yourself from the sadness they caused on you. That's it. Hence, if you manage to lay down your shield once again, the anger will probably vanish the same way it showed up.
She was a pretty girl. She was close to you. You trusted her. She walked away. She's dead. There's nothing to regret.
Now playing: Nine Inch Nails - Ripe (With Decay)