Firebenders have never been a sign of anything good in Asami's life.
She tries not to be afraid when she hears the soft whoosh as a flame erupts from Mako's fist, or the swing of Korra's leg. Since her mother's death, she's never been comfortable around fire.
Asami would silently dare herself to sit in front of the fireplace in her younger days, a safe distance away, her knees hugged to her chest. She would see how long she could wait before the fear was too much to handle. Her own self course in hiding her emotions.
She's seventeen when her heart is broken, once again, by a firebender. This time it wasn't her family he took, but a piece of herself - the idealistic, romantic dreams of an industry princess.
It's no wonder when the third firebender comes into her life, she gives him a little bit of hell.