If you can't already tell, I love Molly Hooper. In a show that sometimes feels a bit short on female characters (for which we can blame the roughly 100-year-old source material), she is the woman who feels the most real for much of the audience, which, it turns out, is mostly female. We've watched and cheered her on as she's grown from a timid, mousy young woman to just your average, ordinary, everyday badass. She dated the world's greatest criminal mastermind and then dumped him, she helped Sherlock Holmes pull off the greatest deception of the century by faking his death, and, on top of it all, she's daring enough to fall in love with Sherlock, which in itself is probably the bravest thing anyone could ever do, and I admire her for it. Molly Hooper is amazing, and here are a few reasons why:
(Warning: spoilers for His Last Vow, airing in the U.S. tonight on PBS)
1) Molly is the only non-canon central character.
Molly Hooper wasn't even supposed to be a recurring character; Steven Moffat and Mark Gatiss were quite adamant that there would be no characters that didn't exist in the Conan Doyle stories. Molly was meant to be a one-off joke in the first episode and then disappear from the series. However, Louise Brealey's performance in the pilot episode was so wonderful that the creators decided to keep her on, and we're so glad they did. It's incredible to see how far the character has come in the series; she has gone from a throw-away side character to an integral part of the show, starting with her essential role in faking Sherlock's death in "The Reichenbach Fall" and expanding to her inclusion in helping Sherlock solve crimes in "The Empty Hearse" and appearing in his mind palace in "His Last Vow" to help save his life. Other non-canon characters may have taken on a greater importance within the show, such as Anderson, who represents the voice of Sherlockians everywhere in "Many Happy Returns" and "The Empty Hearse," but none can beat Molly for making such an originally insignificant character into such an important and beloved part of the show.
2. As far as character development, Molly has grown as much as Sherlock.
Critics and fans alike have made much of how far Sherlock has grown emotionally throughout Season 3, particularly in "The Sign of Three," an entire episode revolving around Sherlock's best man speech where he tells John how much he means to him. This is quite a different man from the one who has insisted that "love is a chemical defect found in the losing side."
As much as we can see Sherlock has changed, Molly has changed, too; she is still quiet and awkward and everything that makes us love her, but in two years she's found her own inner strength. Her love for Sherlock is no longer a schoolgirl crush; she's been through too much for that. He's hurt her feelings, humiliated her in front of their friends, disappeared from her life for two years, and yet, even when she tries to move on by having a relationship with Tom, after Sherlock comes back she finds that she still loves him. She's no longer infatuated, putting him on a pedestal and standing in awe of him; she knows his faults, his frustrating quirks, the manipulative way he can use other people, and she loves him, anyway. Nowhere is this more evident than in "His Last Vow" when she slaps him when he relapses into drug use. Her anger and disappointment in him and his lack of concern for his own welfare as well as the concern of his friends manifests itself in three hard slaps across the face. In this moment we know mousy Molly from "A Study in Pink" is no more; she has graduated from infatuation to tough love. She is done putting up with Sherlock's bullcrap, and I think that is exactly what he needs.
3. Molly's love and open displays of emotion are the counterpoint to Sherlock's callousness.
Now that John will be settling into domestic life with Mary and their child and consequently not spending as much time at 221B Baker Street, someone needs to keep Sherlock on the straight and narrow, relatively speaking. No one is better suited for that than Molly, as can be seen in their temporary partnership in "The Empty Hearse." Just like Sherlock and John balance each other out, the same principle applies to Sherlock and Molly: Sherlock is the mind while Molly is the heart, although they each bring out both qualities in the other. While solving cases, Molly is able to show her intelligence and skills as a pathologist. Sherlock is able to show more of his emotional side when she is there, as can be seen in their conversation on the stairs. In that scene, Sherlock is completely genuine and sincere, a rare occurrence that doesn't happen with any other character in the episode, not even John. I'd like to think Sherlock feels comfortable expressing his emotions because Molly is so open with hers. They've each helped the other grow, and I personally can't wait to see how this incredible friendship continues to evolve in Season 4.
4) Molly gives everyday women an "ordinary" heroine to cheer for.
The show has its share of extraordinary women - Irene Adler, for example, and Mary Watson. We love them (especially Mary) and we love watching them kicking butt and taking names, knowing full well they are the kind of women we will never be. At the end of the day, we need someone like Molly Hooper. She's shy and awkward around the man she has a crush on, and she's not the kind of person you would notice right away; most of us know how that feels. That's why it also feels like a triumph when Molly becomes so central to Sherlock's life, when she becomes the one who counted, the one person who mattered the most. She comes into her own in so many ways, and that gives us hope for finding something extraordinary within ourselves when we feel oh-so-ordinary. At the end of the day, keep your dominatrices and former CIA assassins; Molly Hooper is the woman we see ourselves in, and she gives us hope that we can be half as amazing as she is.
5) Molly Hooper is the epitome of what the show is about: the most insignificant details/people are the most important.
Sherlock bases his whole life, i.e. his work, around the smallest details, the tiniest clues he draws deductions from to solve a case. The real mystery is why it took Sherlock so long to really see Molly; no one notices her - because of that, Sherlock in particular should have noticed. She's been in Sherlock's life even longer than John; as a pathologist, she's closer to Sherlock's work than anyone else ever has been or ever will be. We see Sherlock notice her at the Christmas party in "A Scandal in Belgravia" and when she deduces him in "The Reichenbach Fall"; it's these simple moments that allow him to recognize her potential, and so she becomes "the one person who mattered the most" to him in helping him fake his death and fool Moriarty. Through Molly we can see how the most ordinary person can be extraordinary.