These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Alternative Character Interpretation: If not for their direct interaction with Derek, one could easily assume that the odd personalities of the animals were all in Odette's head, a coping mechanism for dealing with the loss of her father, lover, and home...
Angst? What Angst?: Odette is never seen grieving over her dead father. And no one seems to have any problem in the third movie with Odette being resurrected with necromantic black magic.
Alternatively, the second example is simply Derek's reward for destroying the Forbidden Arts, which wouldn't be a reason for angsting.
Well, she does do a lot of breaking down in the first movie, which can be assumed to be about the whole gravity of the immense situation she's in, from the death of her father to being cursed.
Also, there's no real mention of how much time has passed. Uberta says, "Thinking of her and the way that it was", so possibly a couple of months or even a year could have passed. Maybe, Odette had already mourned and now was focused on escape.
Complete Monster: Rothbart kills King William before placing his Odette under a spell and only being willing to lift it if she weds him. Then to prevent Derek from breaking the spell, Rothbart transforms Bridget into Odette so Derek will make his vow to her instead, knowing this will kill Odette. And he enjoys every minute of such dirty deeds.
Fridge Horror: In the third movie, Odette actually dies. As in dead! But after burning the pages, she is raised from the dead — apparently by the power of forbidden black arts.
From the first movie, where does Rothbart go when he's not in the castle at daytime? hunting anything as the Great Animal of course!
"Funny Aneurysm" Moment: During the opening song, Derek takes out his frustration over the forced betrothal by shooting arrows at a Gonk picture of Odette that he drew. This becomes less amusing after Derek mistakes Odette in her swan form for the Great Animal, and very nearly shoots her for real.
Tainted by the Preview: If the timing of The Swan Princess Christmas (14 years after the end of the trilogy and two years after the death of Odette's original speaking voice) didn't already make it seem bad enough, the trailer's cheap animation and writing quality cinch it.
Tastes Like Diabetes: Each movie ends with Derek and/or Odette saying something sappy, then kissing in closeup (through Stock Footage, no less). From the third movie:
Odette: Promise me, Derek. There's no more magic in the castle?
Derek: I can't do that. So long as you're here, Odette, there will always be magic.
Uncanny Valley: The fourth film, entirely made in CGI, is full of examples.
What an Idiot: The first film would be shorter if the lovers didn't each hold the Idiot Ball. Odette, in her swan form, has to steal a map from inside Rothbart's castle to tell where she is when she could just fly and get an idea that way. And Derek falls for an Odette dupe who is dressed in black. (In the ballet version of this story, this is justified as the lovers have only just met, but here they've known each other for years and she usually wears white.) In the third film, he falls for an Odette dupe again. It's even lampshaded by Zelda.
Though Odette does justify wanting the map as wanting to make sure that she knows where she's going and how to get back - it's only by being at the lake that she can turn back into a human.
Also, we were never given any indication that Odette was familiar with where Rothbart had taken her. Remember, she was in Derek's kingdom with her father when Rothbart had attacked. She's spent most of her summers visiting Derek but that doesn't mean she'd know every square inch of the land.
It's been observed that while Derek isn't a total moron, he's not exactly the most quick witted individual. He did note that the Odette impostor seemed a little different than how Odette usually is, but Bridget's acting and composure as Odette was near flawless. Besides, she was probably pandering to Derek's ego by the way she was hanging on his shoulder and smiling vapidly as he was making his vow. Derek was too in the moment to really notice the change because it seemed too good to be true.
In the third film while Wizzer has Zelda distracted, Derek apparently thinks it's a good idea to shout her name and then attack her as opposed to snatching the wand away and breaking it while she was distracted.