Low on the social ladder, tagalongs usually follow more popular people around everywhere they go. Usually ending up pissing off everyone involved.
2) "Look at that desperate idiot, stalking that girl, loser tagalong"
Therefore, the person decides to stick with the people and hope for the best. He hangs on the edge of the group and follows them from time to time, becoming a "tag-along"
John: Yeah, Mike is such a Tag-along.