It is what someone desperate for human interaction/friends/ a boyfriend does, anyone who is nice is immediently latched onto.  It has happened to me a few times, in college me and my friends were nice to this girl who everyone else ignored and she latched onto us (she had tried a few groups in our class before us) and followed us everywhere.   While we had no hard feelings against her, me and my friend wanted to be alone to be with each other (we are still best friends now) so we would run away and leave class before her so she couldn't catch up but we made it look like chance, not intentional. We didn't want to say it to her face or hurt her feelings, she soon understood and left us alone.  We also had the same thing with a strange guy from Norway except he tried to come to hospital and therapy appointments with me and was really creepy, he said some scary things sometimes so we had to tell our teacher. I am still friends with this girl now but only because she matured and stopped following/being obsessive with people.