DarkLightHitomi:
Basically, there is more to the social element than just skill, yet the systems I know of never account for anything but attribute and skill.
Most systems I've ever worked with tend to include something along the lines of "use this as a guideline" or "common sense prevails." They also tend to include situational modifiers (for things like logically deducing something, or having seen the real truth), something which I can't harp on enough, apparently. Now, those exact words I used typically don't appear, but maybe that's just the systems I play. No system can or will account for every single thing, but that's why there are GMs, and that's why there are passages like the ones I mention, because you're right that 999/1000 most people won't be convinced that what they saw wasn't what they saw. They won't believe the horse was actually an orangutan or something of the like. Most people aren't that easily-fooled... unless they have reason to doubt their own memory.
And that's where the 1/1000 comes in because, believe it or not, it's not that uncommon to not remember something accurately. Talk long enough and with enough authority in your voice and, unless the event is recorded, some people will begin to doubt themselves. Their own minds. It's even better when you have a group to back you up, because then the lie becomes more convincing than the truth. Ever seen Total Recall (or read "We Can Remember It For You Wholesale," the story the movies are originally based off of)? That's what an insanely high Bluff check might be like. It can and is more real to you than the truth, if it's allowed to go on, if nothing breaks the cycle.
Again, there are a lot of contributing factors there, and if another person says "No, it didn't" then it becomes an even harder lie to prove, but there's always that slim chance they pull it off. That's what the modifiers are for, and that's why there are lines about common sense and admissions that the rules don't cover everything in every player handbook I've actually cared to read the introduction for (and, if they don't, they should because let me tell you what...).
DarkLightHitomi:
I for example, am extremely difficult to convince of things because 1, I am logical rather than emotional (most people are emotional and this is what classes focus on manipulating), and 2, my knowledge, experience, and rules (I.E. never take a single source as absolute truth) all play into whether I believe something. I however, do not have the social ability to convince other people of things very well, so it ends up being the equivalent of having high social rolls to avoid being convinced or intimidated, but low social rolls when trying to convince or intimidate others.
I do see the social skills as important because then I can play a character that has more social ability than me the player, but rather than saying that a high roll means I convinced your character, it should be read as my character was very convincing and reasonable to the other player's character.
I can see where you're coming from with this, but I ask you: unless they have an In Character reason to doubt your character's statement, like the example you gave above where they've seen/believe something differently, why shouldn't it mean that they've convinced someone? I mean, I get that there's a little bit more of a choice in the matter the other way, but doesn't that sort of invalidate the roll?
I get that a higher number looks good, and you have to check for a fumble or a critical success in some cases, but if your end roll means "You sound very convincing, but everyone still gets to choose whether or not you actually are" then it seems... arbitrary to roll at all. Why not have everyone roll against it with modifiers? Why not set different difficult checks to overcome (and players can set their own, for all anyone really cares, so long as there's a guideline for what they can set it at and they're willing to accept the results).
Does what I'm saying make sense to anyone? >_> I feel like I'm trying to argue that the roll should have meaning, real meaning, like every other roll in every system does. It has concrete, tangible meaning when you say you rolled a 60 to attack, or a 240 in Occult (because most knowledge levels are tiered, so you get a specific level of information for that sort of roll), or a 1 in Animal Husbandry. I just... I think social rolls should have the same effect, like the 3.5 table someone linked earlier. You don't automatically convince anyone of anything, but their attitude shifts to make them more amenable to what you're saying, or maybe you do convince them to do something for you, but it's...
I think my brain has checked out for the night. It was at full steam earlier in this post and now I've lost it. >_> Sorry about that. I shall return on the 'morrow to hopefully be more coherent.