Shiki and his henchmen's dance sequence towards Nami had most people floored with laughter, her disdain at this made it even funnier. This was made funnier still when you realize that there was no reason for it except for Oda-flavoured wackiness.
At the start of the Straw Hats' assault on Shiki's base, Zoro cuts open one of the doors. Usopp then tries to kick open the next door, only to get his foot stuck in it. An annoyed Sanji then says "This is how you do it!" and kicks open the door himself.
And Usopp is still stuck when the door goes flying. He has to scramble to get into formation with the other Straw Hats.
When the Straw Hats open fire, everyone does it coolly and in a calm fashion. Brook chooses to laugh hysterically.
Sanji's beatdown of Scarlet to save Robin only to get his moment ruined by Brook. Leading to him getting cut off mid-curse when he crashes to the ground and an Insult Backfire from Brook.
Sanji understands the gorilla.
Biri accidentally shocking Nami after escaping Shiki's fortress then his revival of her shortly after.
At the beginning when the movie cuts to Sanji and Usopp with Sanji unintentionally calling animals to them while calling out to Nami and Robin.
Usopp: Don't be so loud! They're gonna cat- IT'S A BUG!!!
Usopp: I'm telling you, stop be so lou- IT'S A BIRD!!!
Usopp: Seriously, you're just wasting energy!
Usopp: OH SHUT UP ALREADY!
It's made funnier when you look closer at Sanji. At first he's okay, but then you see his face getting red, then his bags under his eyes go purple, then he has snot coming out.
Before the opening credits, Robin, Franky and Brook are attacked by a giant fish and a large group of deadly ants. They pass right by Brook, completely ignoring him, though they do eat the fish in seconds. When Franky notes that's because Brook doesn't have any meat on his bones, Brook gets pissed off and promptly doeshis thing on the ants, then claims he's just bones simply because he wants to lose weight.
The first two times Doc Indigo adresses Shiki, it's by pantomine and then when he speaks, everyone is shocked. The fact that Shiki gets surprised twice in a row is funny enough, but the third time it's Indigo's turn to jawdrop, when Shiki nods to his gestures without even letting him translate his message into speech, and says "I see" : Indigo is so surprised that his master understood him that his eyes pop out.