From The New York Times:
In sixth grade they were unlikely friends, the good kid and the bad one, the girl who studied and the one who smoked in the alley. They hung out; they met for lunch. They even walked home from school together, one watching, awestruck, while the other ducked into drugstores to shoplift lip gloss, cigarettes, candy. It couldn’t last. One morning in seventh grade, a nasty note appeared on the tough girl’s locker — and someone told her the writer was her cautious friend. “I would never, ever have done that,” said the friend, Bonnie Shapiro, 45, now a mother of two in Evanston, Ill., who works as a recruiter for a design agency. “But it didn’t matter.” Brushing aside Bonnie’s denials, the tough girl told her she was in for it. Sure enough, after school “she and her friends were outside waiting for me, and I had no one, no gang, no one there to support me,” Ms. Shapiro recalled. “I remember it all clearly — I remember what I was wearing: a yellow slicker, with a pink lining.” Admiration turned quickly to fear. “She became that person for me,” Ms. Shapiro said, “and you just don’t forget.”
Almost everyone picks up a tormentor or two while growing up, and until lately psychological researchers have ignored such relationships — assuming them to be little more than the opposite of friendship. Yet new research suggests that as threatening as they may feel, antagonistic relationships can often enhance social and emotional development more than they impede it.