"You did just fight the god of toilets. So, uhm... don't forget to wash your hands."
Also consider that the deity's only wish for humanity is that they have proper restroom etiquette. Fridge Brilliance kicks in because chances are you've probably seen several trashed bathrooms in your life.
The music coming to a dead stop for a few seconds when Anthony admits he's in love with a demon.
Four times. And the way most of the demons respond to his affections is quite funny.
For example, when you have to hunt down the young-looking demoness Moh Shuvuu to tell her about his crush on her. She mocks him mercilessly, calling him a failure as a man and as a human being for crushing on her, and that while she enjoys eating the brains of humans, eating Anthony's brains would probably make her dumb. After the PC finishes talking to her, she takes her leave, laughing maniacally all the way.
Sector Carina is a demonic shopping center.
"Why is there a shopping mall in the middle of an alternate dimension in Antarctica?"
"This is the brand of cereal I eat back home. I see this box every day." (The crewman opens the box.) "Ew! What is this, mud? Is this what demons eat?... Maybe it's an acquired taste?"
"Hey, welcome to the sector Carina shopping center! Our awful location, lousy selection, and terrible customer service make us #1 in shopper mortality!"
One crew member wonders if the sector accepts credit cards.
If the minion has status ailments when Horkos eats it, Horkos will contract that ailment. In other words, he gets food poisoning.
Jimenez's reaction to meeting Mastema:
Mastema: I'm sure that we will get along splendidly. Provided you learn a bit of etiquette from Zelenin first, that is.
Nearly any dialogue involving NPC demons of the "Beast" personality type (a Boisterous Bruiser with No Indoor Voice). In particular, in the Chaos path, there's a friendly Nidhoggr in Sector Carina who helpfully informs you:
You can trick several demons into joining your party by telling them that you are a girl.
You can also sometimes trick "Young girl"-personality demons into your party by telling them there's a ghost behind them. Bonus points if the demon in question is, in fact, a type of ghost.
On occasion, "refined lady"-personality demons will ask you to compare them to a fruit. The options are a tomato (which sometimes works and sometimes gets "That's not even a fruit!"), a watermelon (which sometimes works and sometimes pisses them off), and... a durian.
Surprisingly enough, the durian is actually the best option to choose for some demons.
On the subject of answers you just know are a bad idea, one of the most common questions demons will ask you is whether you're scared of them. When a "punk"-personality demon asks you, the possible answers are "Yes," "No," and "Your face is hilarious."
Some demons, however, will be impressed if you choose that, applauding your guts to insult them to their face.
In Jack's Squad HQ, you can try talking to Jack's soldiers, who will note that you're trying to use the demon language translator to talk to humans.
In Sector Eridanus, you'll come across Jimenez passed out on a trap floor that puts you to sleep, with Bugaboo jumping around frantically, trying to get you to help him. The hero tries shaking Jimenez. No luck. Then he tries punching him. No luck. Then he kicks him so hard the screen shakes. That wakes him up. And one of the first things Jimenez says? "For some reason, I'm aching all over."
Alot of the descriptions for the achievments you can get are hilarious, A few examples are
"You are fast, Like a child running away. It still seems better to stand and fight, but training your legs is good too."
"You're the King of fleeing we bestow upon you the title of Road Runner. No one has legs faster then yours, or a belly so yellow."
"Ran into walls 255 times! Fear not: the demonica's superior build quality won't get so much as a scratch. The most advanced materials were used to create it, and can take any punishment. ...Even so, 255 times is a bit much. calm down spaz."
"The technical term is "Fixed-perspective movement," but we like to call it "crab walking" thats right, you have crab walked 3000 steps. You have earned the title of Crab Master Try it in daily life to gain an advantage over slow walkers!"
"You fell into a pitfall! This was your first pitfall in the schwarzwelt, wasn't it? how did it feel as you fell? Anyway You've been introduced to the typical cheap trap. Be very careful from this point on."
"...You're not starting to ENJOY falling through pit traps, we hope?"
"Through my charms, your kind will reach their climax and... die!"
Redux provides a meta example. In Shin Megami Tensei IV, the demons known as Mitra and Mithras in the original Strange Journey swapped names. While this wasn't a big deal then, the name swap kept in Redux, where, like in the original, Mitra (now Mithras) is the second Arc Villain and Mithras (now Mitra) is his One-Winged Angel form.