Because only after applying heat can you increase strength and flexibility. (Canon-compliant, Feminist themes)

Arya was scared of very little in her life. Needles. Heels, usually forced on her by her sister and mother for stupid high society events. And, the most recent and terrifying one, telling her boyfriend that he was about to be a father. All of them understandable fears, if you asked her. Actually, telling their families that she's pregnant at nineteen was also a prominent new fear.