Anger

She has Hanahaki Disease which is a disease caused by unrequited love that makes flowers grow inside the lungs. The disease can be deadly, suffocating them in the end, unless treated. The only way to get rid of the disease is having their love returned or surgically removing the flowers. Removing the flowers, however, will render them unable to feel love

"I didn't want to fall in love! It's not like I could control my feelings"