Lord Farquaad, the Big Bad. note Though this might be a coincidence — apparently Lord Farquaad was actually named after one of the quads (as in quadrangles) in The University of Notre Dame du Lac, in Indiana, where many of the filmmakers graduated from. Farquaad was named after the quad that was situated furthest away from the main building, i.e. a "far quad". Especially since he's a caricature of then-Disney CEO Michael Eisner...
One memorable Farquaad moment is when he's watching his bride-to-be in the magic mirror while he's in bed (making the mirror rewind, no less), and he peeks under the blanket at his lap, and gets this pleased "Oh my" sort of expression. If you look closely, you can actually see, ahem, part of the blanket move. The same scene shows a rather... familiar-looking bear rug on his bedroom floor. One with a bow that we spotted on Mama Bear earlier in the movie.
Yet again, towards the end when Fiona sees Lord Farquaad's castle, there's this bit of dialogue.
In the Norwegian dub, when Donkey is being courted by the dragon: "That's sexual harassment!"
Another addition in the Norwegian dub is Donkey exclaiming the equivalent to "Damn".
Pinocchio is wearing ladies' underwear (a thong to be exact). The UK version cuts the actual visual of Pinocchio wearing the thong, but the part where he denies it was left in.
When Donkey drinks the potion, he asks Puss if he looks different. He replies "You still look like an ass to me".
The TV show Knights reports Shrek riding a "white bronco" (Donkey as a stallion), a reference to the O.J. Simpson car chase.
During that scene, some knights can be seen giving the headless horseman a DUI test.
When Shrek, Donkey and Puss are being arrested, a knight finds a bag of catnip in Puss' pocket, which he says is not his. The UK version also cuts this part, as apparently, associating catnip with marijuana (or any other illegal drug you can name) is a no-no if the film wants to get a U rating (the PG cut, however, does have that part).
During the final battle, a pig holds onto the Fairy Godmother's leg and peeks up her dress, shouting "I see London, I see France..."
Shrek has turned into a handsome human and is being fawned over by three maidens. Two of them try to ease the confused Shrek's tension by rubbing his shoulders. The third complains "I don't have anything to rub..."
Additionally, when Puss says Shrek needs to change his clothes, all the girls smile and squee.
Shrek the Third
When Shrek hears that Fiona is pregnant, Puss tries to give him The Talk.
Shrek: How did this happen?
Puss: Allow me to explain. You see, when a man has certain feelings for a woman, a powerful urge sweeps over him.
Shrek: I know how it happened. I just can't believe it.
Donkey:(to Puss) How does it happen?
While Donkey, Puss, and Shrek are looking around the high school campus, two young boys come out of a carriage smoking on the inside. The boys were also wobbling around disoriented and joyful.
One of the boys say something like, "Don't burn all my frankincense and myrrh!" Not even sneaking past the radar.
After Shrek finds out about Fiona's pregnancy Puss says
When Shrek reads that a true love's kiss can render his contract null and void, Donkey, thinking Shrek wants to kiss him, says "You're gonna have to take me to dinner first".
This scene made it into the trailers, too!
The part where Shrek wants Donkey to track down Fiona (after seeing the Wanted posters). Donkey calls her scent "sweet and delicious" to which Shrek replies that it's his wife he's talking about. Turns out he was talking about the pancakes
At the end when the witches take off on their brooms, one of them can't get hers to start. It turns out she's pulling on Pinocchio's nose, and he's smiling too.