Doing a bit of playing prior to launch, and I just saved the Tiefling from the Bugbear assassin. I don't expect her to bow and scrape and call me master, but her sarcasm and lack of gratitude is missing verisimilitude. ''Thank you, mighty slayer of Bugbears.' if there were a dialog option of "How about I just finish the job?" I might be tempted to take it.
The fact is other gaming companies have spoiled you by inundating you with NPC's who are one-dimensional Pollyanna's. IRL people are often not grateful for help because it undermines their own internal locus of control, sense of self-worth, or because they don't know how to express gratitude.
When I was very young I was an EMT - and like as not the family/friends of the injured party would not express gratitude for our attempts to save the life of their loved ones as much as you might expect. Sometimes, they just physically assault you for any number of reasons - "save their life faster" seemed to be a common reason.
Some people WILL straight up resent you for helping them. That's just life. I actually applaud Larian for creating a more realistic range of responses for your 'heroic' actions.
