|Victoria Maderna Illustrates the problem quite nicely.|
The first place where these rules chafe is at the point where rolling dice rubs up against roleplaying. Skill checks are simply dice rolls made to determine the outcome of some task. While such checks make good sense for things like scaling a sheer cliff, escaping from restraints or crafting a magic horn of tootie-fruity--actions that would be ridiculous, dangerous and/or impossible to replicate in the comfort of one’s living room--they might not be so necessary to replicate things like, bartering with a shopkeeper, or interrogating a prisoner. These are in-game activities that can be reasonably approximated with talking and a bit of imagination. No furniture broken.
However, not every player excels at thinking on his or her feet, and if you’ve ever met my fiancee, you’d know that any attempt she made to actually intimidate someone would likely be met by giggles and/or hugs. Having the option to roll dice makes an excellent choice for players who are playing outside their normal personality, or who are friggin’ tired from a day of work.
The second place where the social skill rules tend to chafe is in the way their bonuses are calculated. In 3rd edition D&D, every skill is tied to a particular character statistic. All the social skills happen to be tied to Charisma (i.e. how attractive? persuasive? leadership quality-ish? a character is.) Unfortunately, by this metric, a hulking 7-foot tall half orc (with a -2 racial penalty to charisma) is statistically likely to be less intimidating than a 3-foot tall halfling (no cha penalty). How does that work!?
The rules also fail to account for cultural differences that might arise, like barbarian mistrust of candy-ass bards and their pretty-talk. Thus, it is up to the GM to house-rule and/or shoehorn exceptions to these rules. While this might work for many groups, it might also lead to GM v. Rules-Lawyer in a court of nerd. In my particular house, I will allow players to use an alternate stat modifier on social checks if they tell me how they plan to use it. “I’ll get him to talk by throwing my dagger into his chair two inches below the family jewels” = intimidate + dexterity check.
There is also the issue of how the rules actually play out. The game uses a roll of the dice against a fixed number found on this table to determine how far another character’s attitude is shifted by a check. It is quite possible for a player to acquire enough ranks in their social skills to diffuse even the most rabid animosity and to turn every shop-keep into the player’s new best friend. Furthermore, anyone with even a single point bonus to any of these skills will almost never provoke a negative reaction from someone they try to woo. This fixed target mechanic often leads bards and other social-powerhouse characters to be disparagingly called “diplomancers”. Again, house rules and shoehorns can be employed to fix the issue. Say my character misses with his dagger... the interrogated’s attitude could change in several different negative ways depending on where the knife ended up.
Finally, there is a problem of degree. Some players have the distinct impression that a higher roll automatically equals a better result. While this is true in some cases, in others, the results max out after a certain point. You rolled a 34 while chatting up the previously indifferent barman? Great! He likes you a lot. You are his new best friend. Does that mean he is going to give free drinks to you and everyone else you bring to his bar for life? Not. Bloody. Likely. GMs need to establish, and may need to explain the limits to which a character will go for their new diplomantic BFF.
Meatloaf is so diplomantic, but even he has his limits.