Look What You've Done is a song by Zara Larsson about missing someone after pushing them away. The lyrics express the regret of not realizing the importance of the person until they are gone. The song talks about the desire to tell the person how they feel and the struggle of moving on. The chorus emphasizes the impact the person has had on the singer's life and how they are everything they want and need. The song has a catchy melody and is a popular hit among Zara Larsson's fans.