A very notable theme in Lee's lyrics is relationship struggles. She often identifies various events in life with a story between herself and a lover, evident in the song “What You Want” which is actually inspired by her love for her band and fans. She also writes about her actual relationship struggles, examples include “Call Me When You’re Sober”, referring to her ex-boyfriend Shaun Morgan. Additionally, she often incorporates dark and mysterious themes into the bands’ music, and has mentioned that she is particularly fascinated with the idea of death and beyond. She also resorts to imaginative and picturesque themes as seen in songs such as “Imaginary” and “Lithium”. The songs “Hello” and “Like You” were written in honor of Lee’s deceased sister.