His comments about how humans are mostly water. It includes such things about humans having "all those squishy parts" and wondering "how the constant sloshing doesn't drive you mad". The player has the option to reply, "Neither do I, come to think about it."
Discussing the legal requirements for his type of model (which he evasively clarifies as "the illegal kind"):
PC: There are legal requirements for illegal models? HK: Answer: More than there are for legal models, apparently. That is meatbag logic for you. PC: But... how can illegal models be regulated? HK: Query: Would you rather be caught with contraband that is very illegal, or just a little illegal? PC: What's the difference? HK: Answer: About twenty years, master. PC: Maybe we'll keep you a little illegal, then. HK: Agreement: That was my thought as well, master. You show excellent logical skills... for a meatbag.
The reason he calls everyone meatbags? Because Revan programmed him to say that because it annoyed Malak
During a murder investigation where you have to interrogate two subjects and find out who (if any) is lying, one of the reasons you can give for why someone is lying is "Fat people always lie."
A darkly funny incident on Taris. A group of drunks try to bully you. You can pick a fight with them, in which case they will talk tough, raise their firsts... and abruptly be messily gunned down by every Sith on the street, who will then go back on patrol like nothing happened.
Speak to the Rakatan Elders, and try to explain yourself.
Rakatan Elder Councillor: Is this some type of test, Revan? Some type of trick? You came seeking our aid; you came in search of a way to enter the Temple of the Ancients. You claimed to be seeking a way to destroy the Star Forge, and we were foolish enough to believe you. Unaware of your true nature, we helped you enter the Temple. But you betrayed us, Revan. Instead of destroying the terrible legacy of our ancestors, you unleashed the evil of the Star Forge upon an unsuspecting galaxy. And now you stand before the Council of Elders once more. And once more we ask you: for what reason have you returned, Revan?
PC: Uh... I need to get into the Temple so I can destroy the Star Forge.
During the questions for what kind of Jedi you'll be:
There is a locked door, and you need to get to the other side. What do you do?
Which, by the way, is impossible without tampering with the game files a little.
"I may have lost 52 matches in a row before you, but I figure I've got your number!"
Not reconciling the two feuding families on Dantooine. You can be such a total, totaldick it Crosses the Line Twice back into funny.
It really does, as shown in the second part of this video.
Carth and the female PC flirting, her hurting his "man-feelings". "Don't tell me not to take it personally, you hairless wookiee!"
The PC just loves to toy with Bastila.
Bastila: On which planet were you born?
PC: Kashyyyk. I'm a Wookiee...can't you tell?
Bastila: What is your background?
PC: I'm a Hutt in human form planning to overthrow the Republic.
Bastilla: How old are you?
PC: 3012. Healthy living, you know.
Bastila: I see you intend to be childish about this.
Any attempt to flirt with Bastila. See here for a good compilation.
Teasing Carth works better for a female character.
The male PC's and Bastila's interactions.
PC: "Your face is all scrunched up like a kinrath pup."
Bastila: "A...a kinrath pup? It most certainly is not!"
PC: "Come on, I was only having fun."
Bastila: "Fun? Fun? Driving me insane is your idea of a good time? You...you are a really odd man, do you know that? I simply don't know how to deal with you. All I want to do is help you but you seem determined to drive me mad."
The female PC attempting to romance Carth.
Carth: I don't know, what am I gonna have to do to earn forgiveness?"
PC: "Just a little kiss. How about it?"
Carth: "I...aheh, I really think that we should...um...get going."
PC: "No kiss then?"
Trying to get Carth to open up about his past. You can go with the understanding, patient route... or you can annoy it out of him. And of course, as a female Player Character, you once again derail the conversation into childish bickering.
Carth: Yes, What's on your mind? PC: I want to continue our discussion from before. Carth: I thought I said I didn't want to talk about it anymore. PC: Yes, but I'm bored, so spit it out. (...) Carth: Blast it if you aren't the most frustrating woman to talk to! PC: *I'm* frustrating? Look who's talking! Carth: What? Me? What did I do? PC: Oh, that's rich. Where have you been? Carth: I... *sigh* Okay, I give up. You win.
On Tatooine, a guard won't let you out of the settlement without an access card. If you Jedi Mind Trick him to let you past anyway, he'll explain, and he's just sick about this, that the gate will not open unless he runs your access card through the scanner, but he's so terribly sorry that he can't help you.
Jolee never misses an opportunity to snark. Even Canderous approves.
Lashowe: "Do you know how many Sith there are here on Korriban?"
Jolee: "Twelve! No, wait, Thirteen!"
Canderous: "Nice one, old man."
Jolee: "Thank you, it takes effort to be properly irreverent at my age."
Jolee and his story about "swirling Force" and destiny. "You know, you remind me of someone I used to know. Promising young man, great destiny. Breath like a bantha."
Especially his comment about how sometimes "swirling Force" is just "swirling Force", no matter how many old geezers say "Oooh, destiny!"
And his whole story about the guy who believed his destiny made him invincible so he started talking back to the warlord Kraatnote "Tall fellow, biiig teeth." who had him hostage, got thrown down an intake pipe, bumped into something on the way down, and blew the whole ship to bits.
Choosing Jolee to break you out of prison: first he uses a Mind Trick to get put in a cell on his own. Then he mind tricks the guard into letting him out because he's old and could catch a cold in the cell. Then he uses the mind trick again to convince the guard that he should be punished for letting him escape and so should lock himself in the cell. Finally he drops the mind control just so he can mock the guard some more - and all with a tone of voice that tells you he just loves messing with these weak minded fools.
Guard: "Wh... what just happened? What am I doing in here? Damn you, old man! I'll kill you if I ever get outta here!
Jolee: Then I'll be sure never to let you out. Goodbye sonny! [cheery wave]
On a similar note, taking Jolee with you when first applying for admission to the Sith academy, which arguably Crosses the Line Twice. When you refer to him as a slave, he instantly adopts a servile manner and expresses gratitude that you don't beat him much any more. Even Yuthura is somewhat put off. Also this:
Master loves tombs, don't you, master?
Discussing the Wookie's reverence of him.
"Later, I found out they would say prayers to the Hairless One before venturing into the Shadowlands. Harumph, Hairless One. I used to have plenty of hair, I tell you."
When asking him why he stayed on Kashyyk
Jolee: What can I say, I did it all for the Wookies.
Player: The Wookies?
Jolee: The Wookies!
Asking Jolee of what he know about Korriban.
Jolee: Pfah! Korriban's a rock! Mind the sith.
If you have Jolee, Canderous or HK-47 with you during your conversation with Mekel outside the Sith Academy:
Jolee: "Why not shoot them where they stand? It would at least be more direct."
Canderous/HK: "Thatís what I would do."
Jolee: "Of course thatís what you would do."
"Who designed those Sith uniforms anyway? A Blind Rodian with a sick sense of humor?"
"She tried to bite me through my armor, and you should hear what she said about my mother..."
"Hey, don't treat me like I'm a kid. I ain't a kid. I'm fourteen years old!"
There's a farmer named Jon at the Jedi Enclave, and when he first sees you he demands to know why the Jedi haven't yet done anything about the Mandalorians terrorizing the people of Dantooine. You have three dialogue options as usual, but if you pick a particular one...
Player: We are Jedi. What we decide is right.
Carth: Is that your impression of Bastila? If so, it's a good one.
Juhani is a Gay Option for female characters. If played to the conclusion we get this this exchange.
Juhani: Now that I have shared my thoughts, I don't know what to say.
PC: How about 'thank you'?
The Say My Name montage at the end of the Sandral/Matale feud. Serious situation, hilarious encounter.
Ahlan: There you are, Shen!
Rahasia: Mr. Matale!
Shen: Mr. Sandral!
Anyone else think being given the dialog option to shout your character's name randomly at the end of that would have made it even better?
One of the dialogue options while Ahlan and Nurik are arguing is just your PC screaming SHUT UP!
If you convince Elise's droid to return to her on Dantooine, you can later find Elise and the droid in one of the private rooms of the Jedi Enclave. It's not explicit, but it's still pretty obvious you were interrupting.
Carth: I've never felt so sorry for a droid before.
For clarification the PC comes across Elise who is frantic over the droid going missing, but at first makes it sound like it's her husband. Turns out the droid tried to run off because she was using it as a Replacement Goldfish and, it's suggested, a Sex Bot.
Some other characters have their input on this, such as when Bastila almost does not want to imagine just what Elise and the droid get up to.
Carth: Wow she really misses her droid doesn't she?
Bastila: This is hardly the time for jokes. She's obviously distressed enough as it is.
Carth: I'd say.
Bastila: Carth! Enough.
The Gizka quest. Even the quest log is exasperated by the harmlessly annoying froggy-things.
Several times if a Jedi is in your party and negotiations are going nowhere they might pull out the old Jedi Mind Trick. If Bastila does this she might look around nervously afterwards in case anyone saw her.
Deadeye Duncan can run into you on Manaan and mention how he managed to escape Taris after it was carpet-bombed.
Zaalbar, during his time his time captured by Gamorreans, wasn't fed and got testy for not having his five-square-meals a day. He managed to survive by grabbing one that walked too close and eating their arm off. But he spat it out because it tasted bad. Never mess with a wookie.
There's also Mission's story of how the two met; he picked up one Black Vulkar by the neck who fainted immediately from Big Z's horrible breath, while the other two screamed and ran off. You could just hear Mission laugh as she recounts the tale.
Bastila's retelling of how the Vulkar were able to capture her—she lost her lightsaber—and Carth (playfully) mocking her for it. You can join in and wonder why of all the Jedi in the universe, you got to team up with the "absentminded one". Bastila is not amused...
While on Taris, you get a different response from everyone when you're wearing the Sith armor. This one from a random protocol droid was rather funny:
Random protocol droid: All hail the Sith!
While on the streets of Taris, get into a fight and patrolling Sith Troopers will gun down your enemies for you! You even get the XP and they then resume their patrol like nothing happened.