Why 'Mental Statistics' Matter
Along with Intelligence, WIS and CHA are what is sometimes called mental stats. For most, but not all, characters you will probably consider making one or more of these their lowest stat, in order to raise Strength, Dexterity, or Constitution. This is a consequential decision, because these stats have a major part to play in who your character is when it comes to roleplay, in addition to their mechanical function. While Intelligence is pretty straightforward, WIS and CHA can be harder to play well at low scores and it can be tempting to ignore the -1 on your character sheet especially because these stats can be hard to define.
However, playing out the consequences of these low stats can be incredibly rewarding and help make your characters unique both in themselves and from any subsequent characters you play. Poor and inefficient decisions are the spice of roleplay and RPing the stats your on character sheet is a great way to start pushing your play to the next level.
WIS in the Game
This is how the 3.5 SRD describes WIS:
The kinds of characters that have high WIS are pretty clear from what this implies mechanically: A Ranger who can follow a trail on a mountain, a Druid who can tell what a shrub is thinking, or a Cleric who can perceive a dishonest man at a hundred yards.Wisdom describes a character’s willpower, common sense, perception, and intuition. While Intelligence represents one’s ability to analyze information, Wisdom represents being in tune with and aware of one’s surroundings. Wisdom is the most important ability for clerics and druids, and it is also important for paladins and rangers. If you want your character to have acute senses, put a high score in Wisdom.
You apply your character’s Wisdom modifier to:
Will saving throws (for negating the effect of charm person and other spells).
Heal, Listen, Profession, Sense Motive, Spot, and Survival checks. These are the skills that have Wisdom as their key ability.
What about low WIS? Someone who needs two pairs of glasses to see their own nose, or a person who could walk into a bank that was being robbed and try to make a withdrawal. In game, this might play out as someone who overlooks an obvious trail, who doesn't pick up on the danger of the situation they're in, or who has a very weak sense of self. Maybe all of the above!
CHA in the Game
This is how the 3.5 SRD describes CHA:
Again, high CHA characters are pretty clear. A clever spy who can make themselves look like anyone, a dashing Bard who can hold the attention of a whole room with a tale, or a Paladin whose words can inspire his followers to throw themselves into danger. These aren't necessarily beautiful people but they use their force of personality to draw in those around them.Charisma measures a character’s force of personality, persuasiveness, personal magnetism, ability to lead, and physical attractiveness. This ability represents actual strength of personality, not merely how one is perceived by others in a social setting. Charisma is most important for paladins, sorcerers, and bards. It is also important for clerics, since it affects their ability to turn undead. Every creature has a Charisma score.
You apply your character’s Charisma modifier to:
Bluff, Diplomacy, Disguise, Gather Information, Handle Animal, Intimidate, Perform, and Use Magic Device checks. These are the skills that have Charisma as their key ability.
Checks that represent attempts to influence others.
Low CHA can be as simple as very ugly person, but it is definitely not limited to this. Someone with low CHA would also not be very intimidating or persuasive, such as a high Strength Fighter who comes across as a joke. Taking this further, someone with low CHA might also be hesitant to speak up in a group or in front of a confident person. They might be more of a follower than a leader, contributing to but dependant on a more charismatic leader to give orders that will be followed. They might also be gross or off-putting, picking their nose or staring, missing important social cues or being put off by some or many kinds of particularly group situations.
Why Playing Bad Stats is Good
At this point you might be thinking, 'This sounds terrible. I don't want to be a booger-eating chump getting conned by halflings!' That's OK - you're free to play how you want within the vision of the server. However, you will quickly find that playing out all your stats, and accepting that bad things might happen to your character because of it, will actually lead to really fun interactions and many more ways of playing characters who feel different from each other. RPing low WIS and CHA makes your character a more flawed and thus more fully realized person in the game. It will create new and different opportunities for engagement in the game for you and those with whom you're playing.
Consider a few comparative examples:
Robert Baraetheon [High CHA] and Ned Stark [Low CHA]: A charismatic, persuasive king who can get his way but is largely ignorant of the dangers around him and an out-of-his-depth warrior lord who can't navigate court.
A thoughtful tactician [Low CHA, high WIS] and a charismatic battle leader [High CHA, low WIS]: Ideally they'd work together, with one planning and one leading, but just it's down to the tactician to try to reign in the leader who might otherwise lead a suicidal charge.
A strong but simple soldier [Low CHA, low WIS] and a crafty but sickly thief [High CHA, low WIS]: Being able to lift an anvil isn't much good if you can't tell right from wrong, but lucky your good buddy is there to get you involved in completely legitimate schemes.
A Cleric of Tyr fresh from seminary [High WIS, low CHA] and his Paladin companion [High CHA, low WIS]: The Cleric might be able to fill you in on the finer points of Tyr's soteriology and why it will change your life, but they're terrified of public speaking and rely on their Paladin buddy to do the talking and the real leadership.
Most importantly, remember - spicing up your RP with flaws, errors, and bad decisions doesn't reflect badly on you as a player. On the contrary, it's about making your character a more believable, fully realized figure in the world.