I like this!
" That's MY ship! "- Kill all the looters on top of the crypt and all of their friends inside.
" You served me well, Thrall. "- Kill the injured Mindflayer after winning every diceroll against it.
" Blasted door's? Where? "- Get lucky and open the locked door to the crypt with the thiefskit you find on the way, 30 seconds after encountering Shadowheart and ending her dialogues.
" Eat this one, not that one! "- Free the captured Goblin in the Grove with a disguise-self spell-scroll and throw it to the Harpys to eat, instead of the Tiefling child. ( Must be put in the game by LarianStudios first.

)
(* Able to summon a Harpy once a day as a reward? )
Zariel sends her regards- Kill Karlach and return her head to Anders.
My middlefinger sends it's regards- Kill the Zariel sworn mortals and bring the news to Karlach
Can cannibalism be sin?- Eat from the roasted Dwarf in the Goblincamp while being a Dwarf yourself. ( "Disguise Self" allows to earn this achievement. )
The house... of Nope!- Chose only hostile options when Raphael speaks with you & the group
You can hear me blink, huh? Could you also hear 'this'?- Kill the Duergar group in the Underdark after they ambushed you.
How couldn't you see that coming?- Kill the Beholder in the Underdark.
Seriously - the cows attacked us first!- Kill the Minotaurs.
- What is better as a Zentharim you don't know? A Zentharim you do!- Don't kill a single Zhentarim in the entire first Act and only trade with them until you reach Act 2.