"I can't just shut off my emotions," she snapped, her voice thick with mucus, a side effect of actual tears. It was hard, very hard to fake that voice, the thick sound of something caught in your throat as your body increased in fluids, the tears running back into the mucus membranes, increasing oxygen flow to the nervous system as the mucus tried to clear out.
She could fake cry, it was an easy task for her, but there were obvious differences between tears for dramatic effect (the pretty, shining little tears that matched her pretty little pout), and the tears that made her gag, unwillingly coming as a result from her actual emotions. Those she tried to hide, to not draw attention to, finding them ugly things.