And this is where I am, stuck in the middle with you. I realize not every player has my silver tongue and I don't want to punish them for not being as awesome as I am. And humble, like way more humble than anyone else. But I digress. I just want to see them put in some effort, you know? Just show me a little hustle on the field and I'm a happy GM.
It's not just that as a GM improvisational theater is one of the things that I find most fulfilling. I mean one of the best things that can happen as a GM is for the players to start theatrically playing together and you don't even really need to supervise but can just enjoy the show. I'm a happy GM then, because for once it gets 50% of the spotlight off me and let's me feel like my work has not been in vain.
But for me adjudicating a social interaction is just hard, and it matters to me how the player has approached it for determining what the NPC says or does. The biggest thing for me is not how suave the player is or how well they say things, but how well they've judged the motives of the NPC - something that they could cleverly tease out in conversation. Is this NPC susceptible to bribery, or would they be offended by it? Are they the sort that if you threatened their family they'd back down, or would that make them implacable enemies? Is this person secretly a coward, or strong-willed and courageous? Are they proud or humble? What is it that you could offer them that they really want? Do you have some leverage on this NPC? Just how believable is the lie based on what the NPC actually knows? If the player makes their "sales pitch" based on a correct understanding of the NPC and not an incorrect one, it really has little to do with how charismatic the player is in real life.
It's that sort of thing that determines for me how much the PC's can sway the NPC, and not so much whether the player stutters, or is shy, or has a voice not meant for radio, or sounds lame when they are acting. Good social tactics make more of an impact on how I adjudicate the scene than charismatic pitches with good acting. I want to reward charismatic pitches with good acting, but if I do its generally by a small amount.
And players may end up adopting strategies in their rhetoric that don't reflect the thing that they were going for. It's not uncommon for attempts to persuade to veer off into attempts to intimidate. Those are very different things.
Of course, to me at least, if the player has chosen a character that is just bad at social interaction all the skilled play in the world doesn't mean that they will be successful, the same way that skilled tactics might not let a low-level character kill a dragon because they just don't as a character have the combat skill to implement the plan. And conversely, if the player has created a high charisma diplomacy, then NPCs may just be swayed regardless of how badly the player has misjudged the NPC.
All of this is really subtle and complex and hard to quantify in a set of universal rules. Past interactions, the PC's race or ethnic group, the PC's reputation or social standing, and just how big of a demand the PC is making on the NPC all may influence the DC I offer to succeed. I may have guidelines I've written up ahead of time for common gambits the players might attempt for a particular NPC, and I might have some general guidelines that help me pick DCs, but often I am just trying to ad hoc the closest thing I can to fair rulings while keeping the game going.
