If she was the newbiest newbie you've ever met, it's a good thing you showed her the ropes. Yeah, it stinks she stopped playing, but those things happen. Haven't you ever had a character that you had to stop playing, even if just for a while? Like your computer went on the fritz or maybe something in life just demanded your attention? I had to ditch on my first empowered character because some of my distant relatives needed my help. Any reason she had for leaving, doesn't mean that what you taught her won't help her later if she ever comes back. You should feel good about yourself, not feel angry towards her.