The ferret enemies are constantly farting! THAT'S something you don't see every day!
Most of Debora's dialogue and partychat and other characters reacting due to her abrasive behavior.
Generation 1
Any time you make your character read a book, the game will give a description of what the book says... and always end with the statement that your character can't read.
Unless you somehow complete Uptaten Towers in one run, Pankraz becomes bedridden due to catching the bug from Bianca's father. To emphasize: Pankraz, by far one of the most powerful non-controllable characters you ever have in your party in the Dragon Quest franchise and can weather almost anything, is completely crippled by what the game states is the common cold.
Generation 2
If you take Bianca with you to the hot springs in Stockenbarrel during the day and answer, "Yes," to the woman who asks if you're there to relax, you can get the following party chat line:
Bianca: "Huh! Look who's grown up all of a sudden!"
The DS version gives us a third option, Debora. Unfortunately, she's such a known Rich Bitch that most of the town's males steer clear, despite her looks. After completing the marriage challenge, just before you choose Bianca and Nera... she outright marches downstairs and forces herself as a Third Option! It gets better: If you choose one of the original two, you'll be asked twice if you're sure. Choosing Debora is so out of the left field, that even HER FATHER reacts in pure terror. And it's purely hilarious.
Rodrigo Briscoletti: "A-Are you sure you know what you're letting yourself-I mean, are you certain?" Hello, [Insert Name Here]: Yes Rodrigo Briscoletti: "By the Goddess! You are a lion-hearted man, Madason."
The priest's line "taking the hero to be your lawfully wedded husband... for as long as you both shall be resurrected from death in the church" comment is just a hilarious lampshading on how cheap death is in Dragon Quest or RPG's in general. In particular Debora has a rude response towards the priest.
"What's it to do with you? I don't see why you're asking me all these questions! Just mind you own business and get on with it. Hurry up and get all your holy babble out of the way!"
Generation 3
Dr. Agon got onto a minecart without looking at where it led, leading to him going round and round. For twenty years.
Take Tuppence on the fairy lake and go through the mist.
Bear in mind that at this point they're both on a raft with two other people (some likely family members)/monsters who joined the hero through The Power of Friendship. Really thought this one through, didn't you Tuppence? And after you blow the horn:
I feel as if my unworthy heart has been washed clean as a whistle!
Tuppence thinking he has a chance with Deborah (if you didn't marry her).
Talk to your daughter after rescuing your wife. Rather than crying like her brother, she remarks on her mother's beauty(Bianca) or upbringing(Nera) and compliments you for being a smooth talker. Except when Debora is her mother. In that case she congratulates you for having the balls to marry her.
Nera: "DARLING! I'd be grateful if you could avert your eyes from that...lady."
After beating the Final Boss, the Zenithian Dragon is congratulating you with the traditional thees and thous, and then decides to throw it away and go back to his Dr. Agon Ned Flanders-esque speaking, to the horror of the angel-like Zenithians.
