Written for Day 6 of Fire Nation Week on Deviantart. Prompt was "sacrifice."
"What an exquisite performance," Azula says. "I can't wait to see how you'll top yourself tomorrow."
The words cut deep, but Ty Lee keeps smiling as she stares into the mirror and places her headband on its hook. Ty Lee hates this, hates how Azula pretends to give her a choice. She doesn't want to leave the circus, and she certainly doesn't want to be dragged back to the world she ran away from. But Azula is the princess, and Ty Lee accepted long ago that she has little trust in people and that their friendship will always be partially based on the fear Azula instills in her.
(Ty Lee wonders what made Azula this way. She has only seen the Fire Lord a handful of times and never talked to him, but Princess Ursa was gentle and kind and was the first one by her side the day she fell out of the apple tree to ask her if she was alright.)
Her heart aches whenever she thinks about it, longing for the day Azula will see her as a loyal friend, someone to trust and count on because she cares and not because she's afraid. She longs for the day their friendship will no longer be tainted by Azula's reluctance to trust and her own doubts that stalk her and assail her at moments such as this about whether—deep down—Azula cares at all; or if the moments of fleeting almost-tenderness are just her imagination projecting onto reality what she wants to see, wants to be there rather than what is there.
(She will never say this thought out loud, but for all Azula's cunning and cold perfection, Ty Lee wishes she wasn't such a coward.)
Despite that, though, Ty Lee knows Azula needs her, and that is why she is here now, forcing her to go along on whatever mission the Fire Lord has sent her. And whatever feelings Azula may have about their friendship locked up inside her, Ty Lee cares about her and knows she is hurting no matter how thoroughly she may have convinced herself otherwise.
"I'm sorry, Azula, but unfortunately there won't be a show tomorrow."
(And so she sacrifices her own happiness for Azula's in the hopes that one day Azula will be willing to do the same.)