Revealing mistake: When Donkey and Shrek are walking through the garden area, they pass some sheaves of wheat (presumably.) If you look carefully, you will notice that the wheat stalks were cut, not pulled up, but what were they cut from? There is only bare earth. (00:27:45)
Revealing mistake: When Shrek and Donkey are sitting by the fire and looking at the stars, when Donkey asks Shrek about "our swamp" and Shrek says "We?" When Shrek blinks, his right eyeball is slicing through his upper lid. (00:46:30)
Revealing mistake: When Donkey first meets Shrek, when Shrek confronts the knights, not all the shadows fall the same way. Shrek's shadow is cast forward onto the leader knight, whereas the knights' shadows are off to their left.
Revealing mistake: In the escape scene, before the bridge breaks, Shrek's left arm passes through the ropes.
Chosen answer: Who is "everyone"? The only person surprised he can talk is the one human who is processing the fairytale creatures for banishment, and this was used as a plot device to highlight a joke (between him flying and talking).
MovieFan612 ★
Fiona also says "it talks", after he "saves his ass."
To be fair, she was locked in a castle for the majority of her life, so she wouldn't know that donkeys would be able to talk.
And yet he wasn't the only one surprised by it; watch the scene again and Fiona was surprised, too.