What Pierce brings to the table
When Maggie first joins the show we see a brilliant woman who at an extremely young age, has achieved incredible things. Pierce, who is chief of Cardiothoracic surgery, was initially shy and unaware of just how great she was. However, throughout the past 2 seasons, Pierce begins coming into her own. Meeting her sisters and bonding with her father has offered her a certain confidence and support system that she had been lacking for a while. Pierce has become more bold in her abilities, her love life and her friendships. In Season 13, Pierce had a very strained relationship with her adoptive mother who decided to get a divorce from her father. We see Pierce's personality drastically change during this period and become increasingly hostile towards her mother. For her whole life, Pierce relied on both of her adoptive parents being together and the idea of them getting a divorce changed her outlook on life and love. However, the biggest personality change we see in Pierce comes from two different moments: when her mother dies of cancer, and when she realizes she has feelings for Jackson who helped her through her grief. These two moments have defined Pierce's personality ever since. Pierce has begun realizing that she is young, beautiful, smart and way too young to live a sheltered life.