Why are fashion girls so obsessed with Mary-Kate Olsen's style? Let us count the ways. Along with her sister Ashley, she's been in our lives for decades, evolving into a fashion industry mogul who sets trends, designing the very pieces that women want to wear every single day. Second, an Olsen sighting is somewhat of a rare thing, making us even more acutely intrigued by the twins and their signature style. Lastly (but trust us—we could go on), they look chic and confident no matter what they're wearing. With that, ahead, see some of Mary-Kate's best looks over the years and how to get them.