backstabbing liars

Bumped into an old school friend.  Hadn't seen her since high school.  We were 21.  She comes over to my house unannounced when I've got a bunch of girl friends over.  She stays for a while bagging my friends to me when ever they left the room.  As she's leaving she tells me that she only became my friend in high school because she felt sorry for me because I had no friends. 
That's not the truth.  The truth is I had lots of friends until she went around telling lies about me, telling people I'd said things about them when I hadn't.  People got pissed off with me for saying these things until they realised the only one claiming I'd said stuff was her.  Once they realised she was a two faced liar they unfriended her leaving her totally friendless and the only person who would have anything to do with her after that was me.  Too gullible for my own good.  Truth is I felt sorry for her.  I knew nobody liked her.  Everyone kept telling me they don't understand what I see in her, why I stay friends with her, why I don't just ditch the lying two faced bitch.
So there she is at a my house years later after me being her only friend all throughout high school and she's telling me she feels sorry for me.  I know she said this remark because I had friends over and it rubber her insecurities the wrong way so she had to try and win back some semblance of coolness that she never had.  I laughed, gestured to the friends I had in my house and said to her, "Times have changed.  Now I've got lots of friends," knowing full well she never had groups of girls over like that.  She left looking all dejected and friendless.

It's not a nice thing to do.  Reject her like that and make her feel like a friendless loser.  She can't help hating herself and wanting to put others down so she can feel good about herself for a while.  It's just that finding out years later she was still two faced, still liked to put others down to make herself feel good, not ever having a light bulb moment and seeing that shit doesn't work.  Just made me want to tell it like it is.  That was the last time we ever saw each other and it was years over due.