Are You My Stalker?

Why is it that some people feel the need to search out former friends to find out what they're up to?

In my case, when I moved from Los Angeles to be closer to my family, I left behind a group of friends who were beyond toxic.  That was four years ago and I'm still being watched any way they can.  I just don't get it.  As my friend T says, "Find a new hobby!"  This one "friend" in particular specifically said she would never want to be my friend again.  OK, that's great.  Now MOVE ON!