When you have recruited Pallegina and go to the embassy with her, you have the option to side with her against the task the ambassador is giving her. You then get this wonderful 'Deceptive' dialogue option:
(Lie) Yes, certainly. I will make sure Pallegina fulfills her task. (winks at Pallegina obnoxiously)
In Skaen's Temple, if your Cruel reputation is high enough, the pool of blood will offer you to sacrifice one of your companion for a permanent status bonus. If you do, your companions will react in horror (but won't know you are responsible). If you sacrifice Grieving Mother... No one cares. They don't even know she is here because of her glamour. Doing so will earn you some rather funny reactions from the others, including Durance scratching his buttock with his staff and Edér saying out loud that he is going to eat roasted chicken at the inn, while Grieving Mother is choking in her own blood.
When doing Edér's quest, if you have Grieving Mother in your party, you can ask her to help you with examining an object in order to find some clues about his brother's past. If you decide to do so, you get this little gem (remember than no one realizes who Grieving Mother is exactly, because of her glamour, and that is when they realize she is traveling with you at all):
As with any Obsidian/Black Isle game your team members don't especially like each other, this leads to some pretty snarky comments when someone collapses in battle.
Edér: (after Durance has collapsed) Did it get quiet all of a sudden?
Edér's love of animals is mentioned by Hiravias as a hint towards his secretly soft heart, but it translates to hilarity and adorableness gameplay wise. From having special dialogue with pets to wondering if a druid will let him pet his stelgaer companion (keeping in mind that stelgaer's are massive predatory cats with sabre cat teeth), sometimes it's a mystery how this man is still alive.
This one is more sadly and darkly funny, but during Aloth's personal quest in Act 2, a soul scribe has him relive one of the most traumatic memories of his life: the day his drunken, abusive dad beat him so badly a past soul Awakened. As he lies there paralyzed with fear, the Watcher can respond any number of ways, from gently assuring him that it's okay, to holding his hand, to this loving gem: "[Slap him]"
Between Eder and Sagani...
Eder: Sagani, does your fox bite? Sagani: Yes. Eder: ...can I pet him anyway? Sagani: It's your hand. Eder: I'm gonna pet 'im! (Some time later) Sagani: How's the hand? Eder: Turning purple. Sagani: I warned you not to pet him. Eder: If I'm not supposed to pet him, why is he so soft?!
Aloth and Sagani:
Aloth: So... you've been traveling completely alone for five years? Sagani: I've had Ituumak. Aloth: ...But he can't talk. Sagani: My standards changed around year two.
And another from that pair.
Sagani: Son of a moosefucker! Aloth: I beg your pardon? Sagani: Sorry. Kallu's always telling me to watch my language, 'specially around the kids. Guess I haven't had a reminder in a while. Aloth: What happened? Sagani: One of them heard me tell a joke about a Glamfellen youth with frostbite somewhere... sensitive. Kids repeat everything. Aloth: I meant just now. Sagani: Jammed my thumb. Nothing big.
Sagani is skeptical of the Watcher's ability to perceive souls. When she finally sees you in action, she changes her tune. However..
Sagani: Forgive me if I was a little...skeptical of your abilities before. I can't say I've met a real Watcher before. Eder: Oh don't worry about him. He just likes doing that from time to time. Seems to cheer him up, so I just let him. Aloth: Once you've seen it a few times, the shock wears off. Kana Rua: Every time he goes a little strange in the face I try to see if he can hear anything...It hasn't worked so far. See if you can get him to tell you what the spirit said.
Pellagina's appearance elicits some comments from the others.
Hiravias: So, do you have feathers everywhere? Pellagina: Eccosi? Hiravias: You know... does your tiara match your tailfeathers? Pellagina: We're about to find out if your viscera match your fur. Hiravias: Forget I said anything - I rather value my viscera.
Sagani and Hiravias have this quick exchange.
Hiravias: ...before I knew it, the stelgaer was on top of me and I was face down in the dirt! Sagani: Arrow to the throat. That stops 'em. Hiravias: What? No. I was spiritshifted, and she was in heat. So I aimed for the throat, but not with an arrow...
Durance: With a cat's nose, how is it you've failed to notice your own rotten stench? Hiravias: "Failed to notice"? Hardly - I put work into smelling this way! Durance: I should have expected. Hiravias: I never know what sort of game is downwind. I need to smell like part of nature, not an interloper.
Kana: I have never been to Naasitaq. Is it very cold? What creatures wander the tundra? How are your leaders chosen? Sagani: Do you always ask this many questions? Kana: Well, that's just to get us started! Let me get out some parchment for notes... Sagani: Ask whatever you want. If I don't know, I'll make something up.