Disposition:In order to have NPCs behave more believable their behavior towards you should not just be based on one value, how much they like you, but a few values.
Those values could be:
Hate --- Like
Despise --- Respect
Fear --- TrustSomeone can like you but that doesn't mean he respects you, somebody can fear you and hate your guts.
For a few examples, on being liked:A shop owner might like you because you shop there often but that doesn't mean he'll trust you, as soon as you disappear in a far corner of his shop he'll still peek after you. And it doesn't mean he'll respect you, if you sit on the corner of a house, beaten up, out of luck and broke he won't really give a damn about you, you're just a dry source of cash.
If he really trusts you he will leave you looking through his shop unobserved, if he despises you he won't even let you pick up anything. If he really respects you he'll offer you a hand if you're down, if he fears you he might “have to go” suddenly when you come into his shop and “accidentally” forget to close his money box.
On being respected:You enter the fighters guild and already made yourself a name, people know you did some great stuff, the people in the guild highly respect that. But you're the newbie and another member means the cash gets split up on one more guy so they're not likely to like you very much, given the “newbie” treatment it's even likely they'll hate you.
Depending on your background they might already have some trust or fear into you.
On being trusted:A guy who hates your guts, has no respect or no trust into you, every time he sees you he'd want to hit you over the head with a blunt object.
But then he suddenly gets trapped in a burning building, you rush in to help out survivors. When you find him and tell him you'll lead him out of there it doesn't mean he'll like you but his “respect” in you may be a little higher that moment and he's very likely to trust you since you're his only hope.
While in the case of Hate-Like and Despise-Respect there is a “better” side, it is better to be liked and respected after all (at least in most cases), fear and trust are a double edged sword.
While Trust still is in most cases the better side fear can be useful too. As mentioned with the shop owner example, if he fears you he's more easily threatened, maybe even so much that you can raid his shop and he'll just keep quiet, if you'd do that when he Trust you you'd lose that Trust rather quickly.
People fearing you are generally more easily pushed into a situation that's negative for them like giving you things (robbing them), those who trust you are more willing to do what you say in the believe it won't harm them. And that's also there the “limit” of fearing someone can show.
You could relatively easily threaten someone into stealing something for you and take the jail sentence, but threatening them into jumping off a high cliff that would surely kill them it's likely they'll take on a fight and at least have a chance to make it out alive.
If they trust you and you tell them to steal something they may still do it if you can assure them there won't be any harm. Even further if they REALLY trust you you could get them to jump off said cliff with the right words like “there's a magic portal halfway down the cliff, you won't be harmed”, it could be true after all (seeing as this is a fantasy setting and all
) and they have no reason to distrust you.
Of course if you lied they'll lose that trust into you, probably also combined with losing respect and how much they liked you (if they survive trusting you that is).
I don't think they should be displayed in numbers though, maybe just in steps going from:
Extreme negative – Negative – Slightly negative – Neutral – Slightly positive – Positive – Extremely positiveOr instead of a hard number just have a slider that display it:
Hate_____|-------------------------------|---------------|___Like
Despise__ |------------------------|----------------------|___Respect
Fear_____|---------------------------|-------------------|___Trust
I just personally like something like that better than hard numbers.
In fact it could depend on your “skill” to correctly interpret the others emotion. If you can't interpret them well you just get a “negative – neutral – positive” display, if you're better at it you get a extended version like mentioned above and if you're really good you get the slider display.
Though I think this would too much depend on how people like the system to work so this could possibly a option how it's displayed selectable from the menu (a lot of display options should be selectable but that's another topic).