I always talked to the children about 3 categories of people you know. and how to know where they belong in your life.
An ACQUAINTANCE is someone you may see any place you frequent, someone whose name you know. Your relationship is place specific. This is not someone you exchange phone numbers or personal information with. Your relationship with this person is place specific - you see them and say "Hi" for a brief moment in your day.
A FRIEND is someone you see sometimes. know each others' names, talk to at an event such as sports, office party, club or committee you both belong to. This is not a person you would tell your private information to, or put yourself in harm's way for. We once had two girls in the group home who were roommates. One was from CPS and the other one was from juvenile hall. One night they ran away together. When we found them, Jim and I talked to the one from juvenile hall and the staff talked to the other one. When we discussed the situation with our girl, we asked her what would be the outcome of her choices. She stopped for a minute, and then began to cry. She said, "Oh no, I will go back to the Hall." We asked her what she was thinking and she said, "Well, the other girl wanted to run away, but she didn't know how to survive on the streets, so I went with her to make sure she didn't get hurt. I thought I was being a good friend." We asked her, "Would a good friend ask a friend to do something that would get them placed back in the Hall? What do you think will happen to her?" "Nothing," she replied.
A BEST FRIEND is that person with whom you have developed a deep friendship with, can share personal information with, can't wait to see, want to share your good news with as well as bad news, and can count on for help when you need it. This is NEVER a relationship built on negative behaviors, any of the 7 disconnecting habits, or one that contains lies, deceit, or betrayal.
Talk with your children. Challenge them to think about the people they know, and who they would place in each of the 3 categories. Recognize that anyone can move into the friend category, or even the best friend category - it is their choice. What would make a person worthy of such a move? Discussion is always good, and usually rewarding.