I remember in middle school that a good friend of mine teased me horribly that in the first days of school I wouldn't let her sit next to me, because I wanted to meet new people and seem approachable. I apparently phrased it in some horribly cheesy way like "and then people will just flock to us." I was 13 and while I maybe didn't express myself as eloquently as I could, I still stand by that premise. When you go somewhere with a friend, you rarely make new friends, whereas when you go by yourself you are more likely to strike up a conversation with a stranger. I go regularly to the library's programing with my son and have made a number of acquaintances that way. On days people I've already established a rapport with are there, I am unlikely to make new friends. Happily since people attend so infrequently, I more times than not have opportunities to meet someone new.