V is for: Vicious

I queried a novel a year ago that was a huge FAIL. There were a number of reasons for this - a bad query letter, an over-used concept, first pages that never got critiqued like they should have. (I even hired a professional editor and paid an embarrassing amount of money to get my query package critiqued. Total noob mistake.)

I recently re-read this MS to discover the biggest reason of all for the fail: my MC's Mean Girl potential. In this scene, she's able to manipulate everyone around her to do something pretty vicious. (Just to set the scene, Brecken has just had a fight with Tina, her best friend, about Tina's boyfriend Peter.) 

Brecken pulled her knees up to her chest and wrapped her arms around them. She looked more sad than mad. I frowned.

“I have a feeling,” I said carefully, “that Tina is wrong about Peter.”

“How?” my friends asked. Brecken just looked at me. Her thoughts, usually bright purple, were dimmed tonight.

“Tina thinks he loves her for who she is, right? Well, what if her look changed?”

“How?” Kaylee asked again but Chrystal narrowed her eyes. I thought of eyelashes, Tina’s long, curling lashes. An identical evil smile curled their lips.

“Not permanently, of course,” I continued, moving my gaze to Brecken’s. 

“Something small but huge,” Chrystal murmured. She leaned over to whisper in Brecken’s ear.

“Just a little trim,” I heard Chrystal say right before the screaming started again. Teens were getting slaughtered left and right on TV.

 Brecken went still and the color in her mind was exactly half grey, half purple. She needed a little push so I leaned forward.
            “It’ll be for her good,” I pointed out. “Both her and Peter. It’ll solidify their love…or not. Isn’t it better for her to find out now that he's shallow? If he fails this test and dumps her, you’ll stand by her. You’ll be such a good friend that she won’t ever drop you for a guy. Not after this. Not ever again.”

“You’ll actually be helping her,” Chrystal said.

Kaylee fumbled in her overnight bag and came up with a tiny pair of scissors. She held them in one palm so Brecken could see.

“Wait until everyone is asleep,” Kaylee said. “We’ll help you.”

“We promise,” I said.

“Snip, snip,” said Chrystal.

So...vicious. It drives the tension, makes us wince or gasp, throws our allegiances one way or another. But it's generally a behavior reserved for the baddies. Are there any stories out there where an MC can be vicious without losing your sympathy?