Although previous studies had suggested that friendship--male and female--could be a powerful antidote to stress, more recent research indicates that broken promises, dashed expectations, and other side effects of friendship gone wrong can actually raise the level of stress in our lives, often to disastrous effect.

Every time we cheer the downfall of a powerful woman, we're giving ourselves the message that power is bad and we shouldn't desire it. Every time we revel in a beautiful woman's aging or weight gain, we reinforce the idea that we, too, are less valuable if we are old or overweight. Every time we gloat over a woman's loss of a husband to a younger, prettier rival, we are reminding ourselves that our own relationship is unstable, that someday our man, too, will move on to greener pastures.

And I shuddered at the apparent freedom so many women felt simply to take what they wanted without regard for other women's feelings. It was as though we were all crazed customers at some kind of year-end shoe sale, shoving our fellow females out of the way as we clutched desperately at the few remaining pieces of merchandise. I had the discouraging sense that our culture had created female monsters, dooming us to play out these intense and bitter rivalries almost against our will.

The message couldn't have been clearer: women may rise to the top, but they must seem as though they don't care whether they win or lose. Nice girls care only about being nice. They win only by accident or by someone else's efforts.