This seems to be her catchphrase. Every Doctor has a catchphrase used repeatedly in different situations. Some examples would be David Tennant’s "Allonsy," Matt Smith’s "Geronimo," and Christopher Eccleston’s "Fantastic." It’s not clear whether Peter Capaldi had a catchphrase, but its theorized by fans to be "shut up." When the 13th Doctor is excited about something, be it meeting Rosa Parks, seeing her new TARDIS or regenerating into a woman, she utters the word "brilliant!" It was even her first spoken words on screen when she realized she had regenerated into a woman, with "Oh, brilliant!"
20. Her Speeches!
Every Doctor has a defining speech that makes their character iconic. For Eccleston, it's the "have a fantastic life" speech to Rose when he’s telling her to hide the TARDIS away on Doctor Who Season 1 Episode 13 The Parting of the Ways. 10 has his ‘I’m the Doctor’ speech on Doctor Who Season 4 Christmas Special "Voyage of the Damned." 11’s iconic speech is the Stonehenge monologue, and 12’s is the anti-war speech on Doctor Who Season 9 Episode 8, “The Zygon Inversion.” 13 hasn’t had a truly iconic speech yet, but that’s due to the writing and her finding herself. Instead, she has a bunch of tiny speeches, which are iconic moments in themselves. Favorites include "you didn’t expect to fall in love" speech from Doctor Who Series 11 Episode 7, "Kerblam", "we can evolve while still staying true to who we are" on Doctor Who Series 11 Episode 1, "The Woman Who Fell to Earth," and "you are the maddest, most wonderful thing I’ve ever experienced, and I haven’t even scratched the surface" from Doctor Who Series 11 Episode 9, "It Takes You Away."
21. Her Quick Thinking!
Let’s be real; the Doctor hardly ever has a plan. When she does, it’s a plan in progress. The 13th Doctor is quick on her feet, thinking of a plan to save Carl from the train in a mere quick climb up a construction tower. She doesn’t have a plan on the ground, but she does when they get to the top with by encouragement from Yaz. She comes up with a plan to get her TARDIS back almost the instant they land on the Ghost Monument planet, works out the conspiracy theory at the Kerblam factories and stops it in the same few minutes, and convinces a conscious universe to let her go back to the real world. It's definitely a Ravenclaw if we’ve ever seen one.
22. How Good She looks in Capaldi's Outfit!
It’s always weird seeing a new Doctor in the previous Doctor's clothing. Tennant looked strange in Eccleston’s leather jacket, and Smith looked odd in Tennant’s suit. It didn’t suit either of them; they hadn’t found who they were yet in terms of fashion or mentally. But Jodie is a different case, some cosplays have gotten created of her in Peter Capaldi’s destroyed outfit from Doctor Who Season 10 Episode 12, "The Doctor Falls." She wears it for half of her first episode because she doesn’t have time to change outfits with an alien invasion plot. It shows the trauma she went through, that she’s still processing it, and when she does change, she comes into her own.
23. She's A Hero to Young Girls And Women Everywhere!
For many years, a male got cast as the Doctor. These were all amazing actors, but the show was created by a woman, Verity Lambert. Russel T Davis and Julie Gardener were in charge of most of David Tennant's era, but Steven Moffat took the helm for the 11th and 12th Doctors. The female role of the show was usually the companion, the one singing the doctor’s praises and asking questions. Over time, companions stood up for themselves and became stronger, more well-rounded characters (Sarah Jane Smith, Donna Noble, Rose Tyler to name a few). But they were still in the background. Jodie Whittaker has officially broken the mold (though perhaps after a push from Michelle Gomez as the first female Master) and shows young girls everywhere that they can be the Doctor -- even if they aren’t a guy. The Doctor isn’t male or female. The Doctor is an alien, and anyone can be the Doctor.