The girls' arrival in Cephiro. Umi opts to mix panic, outrage, and high volume to deal with the situation. Fuu, on the other hand, is ridiculous in her attempt to stay calm and rational as though this is a normal situation, insisting on good manners and suggesting that that they arrived by way of Mt Fuji erupting. It only gets worse when Clef arrives.
And Clef himself didn't have it easy either. When he tried to exposition on Cephiro's plight, Umi and Fuu continuously ignore him in favor of asking his fish familiar for a ride back home. He pretty much flips off and then unsummoned the fish as a result.
Fuu tries to get Umi not to worry about plummeting out of the sky: they'd black out long before they hit the ground! "Next thing we know, we'd be fitted for halos."
Hikaru and Fuu's sleepwalking in one of the omakes. First, Umi has to hold Hikaru back from wandering out of the tent, and then Fuu "catches" the somnambula and starts tickling her. The next day, both are left wondering why Umi is so fatigued....
The girls have awoken all the Mashin, they've overcome many foes, and it's time to confront Zagato in their Humongous Mecha, and Mokona points the way... after having claimed not to know where he is. And Umi, once again, is outraged and gives chase... while in the Mashin.
In the first episode, Umi stretching Clef's face comically and calling him short when they meet for the first time.
And then when he tried to anoint Hikaru who's enthusiastic to become a Magic Knight...
Umi: What's this, some roleplay? Clef: A-hem!
Just about everytime the girls (or anyone else for that matter) goes chibi.
Episode 2, Presea has a very good one in the English dub when she's explaining to the girls how to select their initial weapons through their willpower.
Presea: Don't you know how to do anything?! Just close your eyes and think real hard!
In episode 7, the girls decide to try out a device that Ferio had given them several episodes prior that he claimed would make wishes come true when in fact, as seen later in this episode, it's actually a communication device. Umi goes first, wishing that they would rescue Princess Emeraude so that she (Umi) would go back to Tokyo and win an upcoming fencing tournament. She then hands it over to Hikaru...
In the episode "Hikaru and Lantis' Dangerous Journey", after Umi denies that she's pacing around in her worry for Hikaru, Clef tells her to look at where she's standing, resulting in Umi asking when she teleported to her current spot.
Fuu and Windam in the opening of the episode "Hikaru and Friendships Torn Apart". Fuu discovers that she's being held captive aboard the Dome of Fahren. Upon hearing that her Rune-God is alive and well, she realizes that she hasn't once addressed him as "Sir" like she does with every other male and she politely asks Windam about it.
Fuu: I've been calling you Windam ever since the moment we meet at the Sky Shrine. Is that alright with you?
Windam: What does thou mean?
Fuu: Perhaps you would prefer that I call you 'Sir' Windam? But I suppose that would mean, (raises her arms as though she were holding a sword) when I raise my sword to summon you I, I should call out Sir Windam! Instead of the way I've been doing it until now right?
Windam: ...Call me Windam.
Fuu: If that's what you would prefer to be called then I would like you to call me Fuu. ...All right?
Any shouting match between Umi and Tarta is one; both the one in Episode 35 while Umi was locked in the cage, and in Episode 44 after Umi won against both Tarta and Tatra.
When meeting with the innocent kids in Castle Cephiro, Umi got kids to attempt to lift her skirt. She tried to politely tell them they shouldn't do it until 10 years later, and even if they do, they're going to get a kick in the face before that happens. Cue Mokona literally headbutting through Umi's skirt from behind, and the usual 'Umi attempts to splat Mokona with a comical hammer' gag commence.