"You were saying Good Morning!, but you were really thinking Good Night!".
Though Sean didn't find it very funny and for good reason.
Several, but the topper has to be when Og Flynn discovers the remains of the wedding night bed. His awestruck reaction as he blurts out "Impetuous! Homeric!" is classic. What makes it even funnier is that the bed wasn't destroyed due to any passionate love-making between Sean...John and Mary Kate; it was destroyed when he roughly hurled his wife onto it during an argument over her unclaimed dowry and stormed out of the room to sleep in his sleeping bag.
Essentially the entire community of Innisfree's reaction to the Danaher versus the Yank donnybrook. It gets to the point that entire counties are traveling by bus to see the fight.
The town elder (Francis Ford) is on his deathbed, driven there by the despair the whole community was feeling because Wayne was refusing to fight Danaher. The young priest isn't reading the last rites, he's reading from an ancient Irish epic about a heroic battle. And when the noise of the fight reaches his house, the old man perks up with a smile and literally jumps out of bed to go watch the donnybrook.
"Is that a public house?" "Yes, your Lordship." "Are they going in?" "Yes, your Lordship." (with a disappointed tone) "Is the fight over?" "No, your Lordship, that's the end of Round One." "Oh." Rule of Three at its funniest.
The restful bar visit after Round One, as Danaher and Wayne start to warm to each other ("You know, Yank, I'm taking quite a likings to ye." "I'm getting real fond of you, too.") ends with the two arguing over who's buying the drinks, with Danaher tossing his pint into Wayne's face. Wayne's reaction is epic: "Bar Towel!" After leaning over to the bartender to ask for the time, Wayne promptly slugs Danaher out the front door.
"Here's a good stick, to beat the lovely lady with." Once the issue of the dowry is settled, Sean... uh John hands the stick to Mary Kate who tosses it away.
Earlier during the "stretch of the legs" Mary Kate loses one of her shoes. The station manager picks it up and races up to give it back to her. Mary Kate - still getting dragged along by Se... uh, John - takes a moment to thank him for returning her shoe.
The Gaelic confession scene. The audience can't entirely understand what the confession is about until Mary Kate has to speak in English because there's no exact words for 'Sleeping bag'.