If you are upset about something your child did, don't attack his or her friends—monitor your own child's behavior. Children resent it when their parents think of them as "angels" and their friends as "devils."
Get to know the parents of your child's friends, so that you can talk to each other and supervise better. Adolescents need monitoring for reasons like the "risky shift." Remember, even good kids need monitoring.
Invite your child's friends over to your house so you can get to know them. And, remember, the more they're under your supervision, the better behaved they'll be!