After beating Bonus Boss Dark Ifrit in the PAL version, you're treated to a cutscene in which the SOB who summoned it is eaten by a fiend. Although the Dark Valefor one is pretty funny too (Evil Bald Summoner Guy gets pwned by a little girl, and runs away from the angry villagers).
The party meets Dona. She tosses off insults at Yuna, while her massive guardian stands behind her. And then...he speaks. "You're Auron, aren't you? May I shake your hand?" Dona is left completely wrong-footed.
You forgot to mention that the insults were about Yuna's many guardians, referring to them as "riff-raff". And Auron is a legendary guardian. Wakka and Lulu then mock her for inadvertently insulting such a famous figure.
"Touch me with that hand and I'll remove it!"
Then of course there's all these exchanges in battles:
Tidus: (to Auron) Don't break any bones, old man! Wakka: (facing a Behemoth) How many steaks you think we can get outta this? Rikku: (facing a Dark Flan) Oooh, is that edible? Lulu: (using Bio for the first time) This might help your complexion. Wakka: (facing a Giant Worm) Where's de early bird when you need 'im?
(When Yuna, Lulu, and Wakka are all out at once...)
Yuna: A lotta fiends here, ya? Lulu: Don't talk like that.
(When Yuna, Tidus, and Lulu are all out at once)
Tidus: Yuna! Aeon! Lulu: Just who do you think you are?
Tidus: They say Seymour went to Macarena Temple. Wakka: Macalania Temple. Tidus: Aye!
Doubly funny when you live in Sevilla, Spain, where the Macarena Temple is a place that really exists (the Holy Basilica of Our Lady Of Hope Macarena, to be precise).
Or as a Filipino, where it's the name of a dance.
After the party is informed about the Chocobo Eater on the Mi'ihen Highroad:
Tidus: A large fiend... Let's go after it! Auron: Why? Tidus: It's the right thing to do! Auron: 'It's the right thing to do?' *chuckles* Tidus: What's so funny?? Auron: Jecht would say the same thing. And every time he said it, it meant trouble for Braska and me.
Before fighting Evrae on top of Cid's airship, you can shop for weapons from Rin. After you've bought everything you need, this exchange happens:
This troper believes the infamous laughing scene is this in a So Bad It's Good kind of way.
Tidus clowning around on the S.S. Liki with the binoculars always makes this troper start giggling.
Try talking to the binoculars guy after that. He runs from Tidus in fear!
When the party is reuniting in the Bikanel Desert:
Rikku: Umm… There's something I wanna tell you guys, but promise not to say anything! Wakka: *camera zooms in on his face* HM?! *glares* Rikku: And no glaring, either!
Another funny part that happens in the Bikanel Desert is when the player finds Kimahri, who keeps trying to walk up a steep sand dune despite falling back down it repeatedly.
Auron's story about Jecht meeting his first Shoopuf. He was drunk and thought it was a demon, so he attacked it. Braska and Auron had to offer all the money they had as an apology, and Jecht never drank again.
After the serious conversation at Home about not telling Tidus what would happen to Yuna, we get this sole line from Kimahri: "It's quiet. Kimahri goes now." This troper finds it hilarious.
Rikku's freak out in the Thunder Plains, followed by the party coming across an inn and Rikku begging to stay there. The way everyone except Tidus keeps walking away from her as you talk to her is too funny.
Kimahri telling Tidus in no uncertain terms to hold still until Yuna gets her new aeon. "Pick spot. Shut up. Wait." He speaks for all of us there.
"RIDE ZE SHOOPUFF??"
An unintentional moment is made by an animation error on Seymour during the wedding scene, while Mika is threatening Yuna (at around 4:28).
The whole cast good-naturedly poking fun at Yuna when she wakes up with bedhead. The entire scene is hilarious, but Auron really takes the cake:
