Prefacing this with: anything Eugenides does, ever.
Attolia's rise to power. Her father married her off to an ambitious family who planned to use her position as a minor princess to seize the throne. Because she acts like a stupid Shrinking Violet, they openly discuss their treasonous plans around her while she collects coleus leaves and catalogs her jewelry. Accordingly, her brother mysteriously dies shortly after he takes the throne, and her husband formally marries her to take the kingship. He gloats loudly until he takes a sip of wine from her cup (which she has been fake-drinking from because it's full of coleus poison). Then when a courtier demands she marry him as her erstwhile husband is cooling, she orders one of the guards to kill him, having bought them all off with her jewelry.
Gen taking on the whole Queen's Guard and winning. Even when one of them turned out to be trying to kill him, he hardly thought of him as a threat at all!
The following exchange. And even better is the attendants' reactions.
Attolia: Ninety-eight days. You said it would take six months.
Euginides: I like to give myself a margin when I can.
The entire first book is revealed as one for Gen. Not only has he managed to retrieve Hamiathes' gift for his cousin, the Queen of Eddis, but it's revealed that the entire book was his plan to make sure Eddis wouldn't have to marry Sounis. Even better, it becomes clear on rereading that he has never once outright lied.
Conspiracy of Kings: The new king of Sounis has to be elected by the council of barons. Sophos gives an impassioned speech about uniting with Eddis and Attolia against the Mede threat, cooperation, and other such things that cast him as a Wide-Eyed Idealist to a bunch of hard, cynical men... so they vote him down, and the Mede ambassador gloats appropriately by asking if he really expected that to work. "Not on the first vote," says Sophos. And then he shoots the leader of the rebellious barons dead, and holds the ambassador at gunpoint — specifically because if he were to aim at anyone else, the other barons might think they were safe. The barons unanimously vote him in as king.
In The King of Attolia, the title king Eugenides is considered by most of his people to be an idiot, a usurper and a barbarian. His attendants live to play pranks on him, egged on by Sejanus, a favored younger son of the most powerful baron. Then their helpless, inept monarch proceeds to reveal that he knows who exactly is responsible for each of the pranks pulled on him, drive Sejanus to confess to regicide in front of the attendants who have just been placed in a very compromising position by him, and exile Sejanus' older brother, thereby bringing an end to the house of the most powerful baron in Attolia. Then, a few minutes later, he and his queen have a discussion that reveals that he promised to destroy the baron in six months and did it in 98 days.
Later, this same king takes on member after member of the king's own guard and defeats every single one of them, culminating in an Ironic Echo -
Eugenides: You forgot it's a wooden sword.
Let's face it, everything the king does is awesome, from the way he serves wine—juggling a cup one-handed while he puts the other cup down—to the way he demonstrates his faith— getting drunk while jumping from crenelation to crenelation on the outer wall of the palace—to the way he convinces the Queen—and everyone else in the palace—that he is not seriously injured by constantly whining that he is going to die. They should just get it over with and rename him His Royal Awesomness.
And Eugenides's moments in the earlier books. Kidnapping Sounis's advisor out of his own palace when Eugenides had only one hand has to count, as does the sequence where he kidnaps Attolia, of all people, and then successfully persuades her to marry him. And from the first book, the revelation that he's been an Unreliable Narrator the whole time and he's hid not only the fact that he's a Rebellious Prince but that he's had the MacGuffin for the last third of the book and has pulled the wool over the eyes of every last member of the cast, including the Manipulative Bastard.
Every last member of the cast, and the reader, which in my opinion doubles as a Moment of Awesome for Turner herself. Seriously, as soon as I got over the shock of the big reveal, my first thought was, how did she DO THAT? And she does it every book!
Then there's the backstory of the Queen of Attolia. She was treated as a political nothing her whole life, married off and intended as a complete puppet - and with minimal political training and no assets whatsoever, she took control of one of the most politically unsettled countries in the world and ruled it absolutely. Keep in mind that it's implied that ruling queens are not the norm. And then there's what she did to Nahuseresh... she kept him believing, in spite of the above evidence, that she was a puppet, was aware of every single step of his Xanatos Speed Chess, and shot his game down completely with The Plan of her own. Complete with a freaking epicBreaking Speech. Badass Magnificent Bitch all the way.
After gaining a reputation for the rather long wait time between books, Megan Whalen Turner shocked the fandom with the completely out-of-the-blue release date announcement for the sixth book only one year after releasing Thick as Thieves — which was about three or four years before anyone was expecting or looking for it! Coming on the heels of the seven year wait between books four and five, the short two year wait for Return of the Thief was a wholly unexpected and awesome surprise.